The U.S.graduate admission system is a highly,if not the most,advanced system of its kind in the world.Much can be learned from this system and can be applied to improve other educational systems.This essay summarizes...The U.S.graduate admission system is a highly,if not the most,advanced system of its kind in the world.Much can be learned from this system and can be applied to improve other educational systems.This essay summarizes the components of the U.S.graduate admission process,analyzes the features of the system,and raises points of the U.S.system that might be helpful for improving China’s graduate admission system.展开更多
Question-Answer systems are now very popular and crucial to support human in automatically responding frequent questions in manyfields.However,these systems depend on learning methods and training data.Therefore,it is ...Question-Answer systems are now very popular and crucial to support human in automatically responding frequent questions in manyfields.However,these systems depend on learning methods and training data.Therefore,it is necessary to prepare such a good dataset,but it is not an easy job.An ontol-ogy-based domain knowledge base is able to help to reason semantic information and make effective answers given user questions.This study proposes a novel chatbot model involving ontology to generate efficient responses automatically.A case study of admissions advising at the International University–VNU HCMC is taken into account in the proposed chatbot.A domain ontology is designed and built based on the domain knowledge of university admissions using Protégé.The Web user interface of the proposed chatbot system is developed as a prototype using NetBeans.It includes a search engine reasoning the ontology and generat-ing answers to users’questions.Two experiments are carried out to test how the system reacts to different questions.Thefirst experiment examines questions made from some templates,and the second one examines normal questions taken from frequent questions.Experimental results have shown that the ontology-based chatbot can release meaningful and long answers.The results are analysed to prove the proposed chatbot is usable and promising.展开更多
This study explores the effects of recent changes in China’s dance college admissions,which now equally weigh academic and professional performance.While the policy aims to create fairer admissions,it presents challe...This study explores the effects of recent changes in China’s dance college admissions,which now equally weigh academic and professional performance.While the policy aims to create fairer admissions,it presents challenges for students from specialized dance programs(keban),who may struggle with academic demands.In contrast,academically strong students with limited dance training may gain an advantage.The research highlights the policy’s mixed impact and proposes flexible admissions strategies,such as conditional offers and ongoing academic support,to better accommodate students with diverse abilities.The study underscores the importance of refining these policies to ensure greater equity and cultural diversity in dance education.展开更多
In this paper, a novel admission scheme is proposed which provides high degrees of quality of service (QoS) guarantees for multimedia traffic carried in mobile networks. The proposed scheme combines the admission cont...In this paper, a novel admission scheme is proposed which provides high degrees of quality of service (QoS) guarantees for multimedia traffic carried in mobile networks. The proposed scheme combines the admission control and bandwidth reservation to guarantee QoS requirements. It considers both local information and remote information to determine whether to accept or reject a connection. In order to embody the characteristics of the algorithms proposed in the article, two traditional algorithms of admission control are used for comparison. In the end of the paper the simulation analyses are given and the results show that the proposed algorithm can adjust the bandwidth according to the current status of networks and decrease the probability of connections forcibly dropped. The most important thing is that the algorithm is based on the multimedia communications and can guarantee the QoS of real time connections through decreasing the bandwidth of non real time connections.展开更多
Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic...Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic of variable bit rate, so decreasing its bit rate can reduce the load of the system, consequently the system can admit new call which should be blocked when the system is close to full load, therefore new call＇s access probability increases. This paper brings forward design project and does system simulation, simulation proves that DCAC can effectively decrease calls＇ blocking probability and increase the total number of the on-line users.展开更多
Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temper...Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temperature can impact human health and the thermal stresses can lead not only to direct deaths and illnesses,but also to aggravation of respiratory disease[3-4].Though the independent展开更多
Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless network...Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks. In this paper, we develop an executable top-down hierarchical Colored Petri Net (CPN) model for multi-traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system. By theoretic analysis and CPN simulation, it is demonstrated that the CPN model is isomorphic to Markov Chain (MC) assuming that each data stream follows Poisson distribution and the corresponding arrival time interval is an exponential random variable, and it breaks through MC's explicit limitation, which includes MC's memoryless property and proneness to state space explosion in evaluating CAC process. Moreover, we present four CAC schemes based on CPN model taking into account call-level and packet-level Quality of Service (QoS). The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performance with less computational complexity in addition to its flexibility and adaptability to different scenarios.展开更多
Objective To evaluate the utility of computed tomography perfusion(CTP)both at admission and during delayed cerebral ischemia time-window(DCITW)in the detection of delayed cerebral ischemia(DCI)and the change in CTP p...Objective To evaluate the utility of computed tomography perfusion(CTP)both at admission and during delayed cerebral ischemia time-window(DCITW)in the detection of delayed cerebral ischemia(DCI)and the change in CTP parameters from admission to DCITW following aneurysmal subarachnoid hemorrhage.Methods Eighty patients underwent CTP at admission and during DCITW.The mean and extreme values of all CTP parameters at admission and during DCITW were compared between the DCI group and non-DCI group,and comparisons were also made between admission and DCITW within each group.The qualitative color-coded perfusion maps were recorded.Finally,the relationship between CTP parameters and DCI was assessed by receiver operating characteristic(ROC)analyses.Results With the exception of cerebral blood volume(P=0.295,admission;P=0.682,DCITW),there were significant differences in the mean quantitative CTP parameters between DCI and non-DCI patients both at admission and during DCITW.In the DCI group,the extreme parameters were significantly different between admission and DCITW.The DCI group also showed a deteriorative trend in the qualitative color-coded perfusion maps.For the detection of DCI,mean transit time to the center of the impulse response function(Tmax)at admission and mean time to start(TTS)during DCITW had the largest area under curve(AUC),0.698 and 0.789,respectively.Conclusion Whole-brain CTP can predict the occurrence of DCI at admission and diagnose DCI during DCITW.The extreme quantitative parameters and qualitative color-coded perfusion maps can better reflect the perfusion changes of patients with DCI from admission to DCITW.展开更多
Considering the advantage of interleave-division multiple-access(IDMA) technique and the technical bottlenecks in the existing satellite systems,IDMA is introduced into satellite communication networks.To further vali...Considering the advantage of interleave-division multiple-access(IDMA) technique and the technical bottlenecks in the existing satellite systems,IDMA is introduced into satellite communication networks.To further validate the IDMA into satellite systems,an effective call admission control(CAC) is proposed to maximize the resource utilization.After establishing the multi-beam satellite system model based on variable spreading gain(VSG) IDMA,the power allocation scheme based on SINR evolution technique and transmission rate adaptation for nonreal time interactive traffic are designed as integrated parts of the CAC,working together to improve the system performance in terms of power efficiency and throughput.Further,the analysis and simulation results show that IDMA under the proposed scheme can provide better QoS,in terms of the blocking/dropping probability,outage probability as well as delay performance.展开更多
Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very sca...Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme.展开更多
BACKGROUND The literature has discussed the relationship between environmental factors and depressive disorders;however,the results are inconsistent in different studies and regions,as are the interaction effects betw...BACKGROUND The literature has discussed the relationship between environmental factors and depressive disorders;however,the results are inconsistent in different studies and regions,as are the interaction effects between environmental factors.We hypo-thesized that meteorological factors and ambient air pollution individually affect and interact to affect depressive disorder morbidity.AIM To investigate the effects of meteorological factors and air pollution on depressive disorders,including their lagged effects and interactions.METHODS The samples were obtained from a class 3 hospital in Harbin,China.Daily hos-pital admission data for depressive disorders from January 1,2015 to December 31,2022 were obtained.Meteorological and air pollution data were also collected during the same period.Generalized additive models with quasi-Poisson regre-ssion were used for time-series modeling to measure the non-linear and delayed effects of environmental factors.We further incorporated each pair of environ-mental factors into a bivariate response surface model to examine the interaction effects on hospital admissions for depressive disorders.RESULTS Data for 2922 d were included in the study,with no missing values.The total number of depressive admissions was 83905.Medium to high correlations existed between environmental factors.Air temperature(AT)and wind speed(WS)significantly affected the number of admissions for depression.An extremely low temperature(-29.0℃)at lag 0 caused a 53%[relative risk(RR)=1.53,95%confidence interval(CI):1.23-1.89]increase in daily hospital admissions relative to the median temperature.Extremely low WSs(0.4 m/s)at lag 7 increased the number of admissions by 58%(RR=1.58,95%CI:1.07-2.31).In contrast,atmospheric pressure and relative humidity had smaller effects.Among the six air pollutants considered in the time-series model,nitrogen dioxide(NO_(2))was the only pollutant that showed significant effects over non-cumulative,cumulative,immediate,and lagged conditions.The cumulative effect of NO_(2) at lag 7 was 0.47%(RR=1.0047,95%CI:1.0024-1.0071).Interaction effects were found between AT and the five air pollutants,atmospheric temperature and the four air pollutants,WS and sulfur dioxide.CONCLUSION Meteorological factors and the air pollutant NO_(2) affect daily hospital admissions for depressive disorders,and interactions exist between meteorological factors and ambient air pollution.展开更多
Among various radio sources which control different dependencies/functions, in this article, we will talk about the Call Admission Control (CAC), and we are supposed to confine our concentration on W-CDMA which is bas...Among various radio sources which control different dependencies/functions, in this article, we will talk about the Call Admission Control (CAC), and we are supposed to confine our concentration on W-CDMA which is based on high raised platforms, since during the recent years remarkable amount of attention has been focused on platforms located in stratosphere layer [1]. Firstly, we study the capacity of uplink from HAP (High Altitude Platform) W-CDMA and we’ll work on estimation and power control defects in a new conversation added to current conversations. We’ll enhance the Call Admission Control (CAC) based on the side effects of power control defects and users’ stimulus and then compare the CAC which has been measured by using of momentary energy on bit in the spectral density form (Eb/N0). Then we examine the mentioned charts for two different criteria which the decision will be made by these criteria in order to decide if exchanged calls are to be admitted or not. The first criterion is based on the minimum of (Eb/N0) of the first row cells meanwhile the second criterion is based on the average of (Eb/N0) of first row-cells.展开更多
This paper proposes the use of admission and traffic control schemes for real-time applications. The admission control scheme determines the admission of high-priority real-time applications such as voice and video st...This paper proposes the use of admission and traffic control schemes for real-time applications. The admission control scheme determines the admission of high-priority real-time applications such as voice and video streams in terms of their bandwidth utilization time (medium time), whereas the traffic control scheme maintains the communication quality of applications permitted admission by restricting other traffic. Owing to the use of contention-based access, a conventional scheme without admission control will degrade the communication quality when the number of terminals using high-priority applications increases. Moreover, only the capabilities (i.e., frame and sequence procedures) of admission control are defined in the IEEE 802.11e standard;the detailed usage in terms of the application characteristics is not specified, and it may be difficult to achieve a sufficient level of quality of service (QoS). The proposed schemes achieve the optimum QoS for actual services. The software used in the proposed schemes was implemented into hardware at the access point, and was evaluated experimentally. Based on the evaluation results, excellent performances with high QoS applications were obtained.展开更多
Network slicing is envisioned as one of the key techniques to meet the extremely diversified service requirements of the Internet of Things(IoT)as it provides an enhanced user experience and elastic resource configura...Network slicing is envisioned as one of the key techniques to meet the extremely diversified service requirements of the Internet of Things(IoT)as it provides an enhanced user experience and elastic resource configuration.In the context of slicing enhanced IoT networks,both the Service Provider(SP)and Infrastructure Provider(InP)face challenges of ensuring efficient slice construction and high profit in dynamic environments.These challenges arise from randomly generated and departed slice requests from end-users,uncertain resource availability,and multidimensional resource allocation.Admission and resource allocation for distinct demands of slice requests are the key issues in addressing these challenges and should be handled effectively in dynamic environments.To this end,we propose an Opportunistic Admission and Resource allocation(OAR)policy to deal with the issues of random slicing requests,uncertain resource availability,and heterogeneous multi-resources.The key idea of OAR is to allow the SP to decide whether to accept slice requests immediately or defer them according to the load and price of resources.To cope with the random slice requests and uncertain resource availability,we formulated this issue as a Markov Decision Process(MDP)to obtain the optimal admission policy,with the aim of maximizing the system reward.Furthermore,the buyer-seller game theory approach was adopted to realize the optimal resource allocation,while motivating each SP and InP to maximize their rewards.Our numerical results show that the proposed OAR policy can make reasonable decisions effectively and steadily,and outperforms the baseline schemes in terms of the system reward.展开更多
Satellite communications has been regarded as an indispensable technology for future mobile networks to provide extremely high data rates,ultra-reliability,and ubiquitous coverage.However,the high dynamics caused by t...Satellite communications has been regarded as an indispensable technology for future mobile networks to provide extremely high data rates,ultra-reliability,and ubiquitous coverage.However,the high dynamics caused by the fast movement of low-earth-orbit(LEO)satellites bring huge challenges in designing and optimizing satellite communication systems.Especially,admission control,deciding which users with diversified service requirements are allowed to access the network with limited resources,is of paramount importance to improve network resource utilization and meet the service quality requirements of users.In this paper,we propose a dynamic channel reservation strategy based on the Actor-Critic algorithm(AC-DCRS)to perform intelligent admission control in satellite networks.By carefully designing the longterm reward function and dynamically adjusting the reserved channel threshold,AC-DCRS reaches a long-run optimal access policy for both new calls and handover calls with different service priorities.Numerical results show that our proposed AC-DCRS outperforms traditional channel reservation strategies in terms of overall access failure probability,the average call success rate,and channel utilization under various dynamic traffic conditions.展开更多
BACKGROUND. The intensive care unit provides critically ill patients with the necessary monitoring, care and supports to optimize their organ/system functions. Parturients are often at risk of sudden deteriorations or...BACKGROUND. The intensive care unit provides critically ill patients with the necessary monitoring, care and supports to optimize their organ/system functions. Parturients are often at risk of sudden deteriorations or exacerbation of chronic illnesses from direct or indirect causes and would often require admissions into the intensive care or high dependency unit. This study is aimed at looking at the trends of maternal admissions in 365 days at the intensive care unit of a tertiary teaching hospital in Southern part of Nigeria, a country that contributes significantly to the global proportion of maternal morbidity and mortality. METHODS. The study adopted a retrospective approach. All critically ill parturients admitted and requiring organ support or close monitoring in the ICU had their files and ICU documents reviewed. The review was held from January-December 2018. RESULTS. Thirty-nine (39) parturients with a mean age (years) of 33 ± 1.3 were admitted, representing 2.9% of annual deliveries. All admissions were postnatal and came predominantly from the unbooked labour ward (51%) and the time lag from maternal deteriorations to presentation to the ICU was 72 ± 10 hours. The main indications for admissions were due to postpartum haemorrhage (33.3%), complications of hypertensive disorders of pregnancy (30.9%) and sepsis (25.6%). Nineteen (48.7%) patients died from obstetric haemorrhage, complications of hypertensive disorders of pregnancy, sepsis and pulmonary embolism. CONCLUSION. The trend of maternal admissions at this specific time frame reflects the burden of maternal critical care in our environment. It highlights the need to holistically tackle the known scourge with improved care.展开更多
Objective:To explore the effects of daily mean temperature(°C),average daily air pressure(hPa),humidity(%),wind speed(m/s),particulate matter(PM)2.5(μg/m3)and PM10(μg/m3)on the admission rate of chronic kidney ...Objective:To explore the effects of daily mean temperature(°C),average daily air pressure(hPa),humidity(%),wind speed(m/s),particulate matter(PM)2.5(μg/m3)and PM10(μg/m3)on the admission rate of chronic kidney disease(CKD)patients admitted to the Second Affiliated Hospital of Harbin Medical University in Harbin and to identify the indexes and lag days that impose the most critical influence.Methods:The R language Distributed Lag Nonlinear Model(DLNM),Excel,and SPSS were used to analyze the disease and meteorological data of Harbin from 01 January 2010 to 31 December 2019 according to the inclusion and exclusion criteria.Results:Meteorological factors and air pollution influence the number of hospitalizations of CKD to vary degrees in cold regions,and differ in persistence or delay.Non-optimal temperature increases the risk of admission of CKD,high temperature increases the risk of obstructive kidney disease,and low temperature increases the risk of other major types of chronic kidney disease.The greater the temperature difference is,the higher its contribution is to the risk.The non-optimal wind speed and non-optimal atmospheric pressure are associated with increased hospital admissions.PM2.5 concentrations above 40μg/m3 have a negative impact on the results.Conclusion:Cold region meteorology and specific environment do have an impact on the number of hospital admissions for chronic kidney disease,and we can apply DLMN to describe the analysis.展开更多
Introduction: Labour admission cardiotocography (CTG) is commonly used non-invasive method of fetal monitoring in Sri Lanka. It may have a potentialto predict perinatal outcome in low-risk term pregnancies. Objectives...Introduction: Labour admission cardiotocography (CTG) is commonly used non-invasive method of fetal monitoring in Sri Lanka. It may have a potentialto predict perinatal outcome in low-risk term pregnancies. Objectives: Objectives of the study were to determine the perinatal outcomes of normal, suspicious and pathological admission CTGs and role of labour admission cardiotocography as a predictive test for perinatal outcome in low-risk term pregnancies in spontaneous labour. Methods: This study was a prospective observational study done involving 445 low risk, term pregnancies in spontaneous labour. Labour admission CTG was performed in each pregnancy and categorized into normal, suspicious and pathological CTG according to criteria depicted by National Institute of Clinical Excellence (NICE) guideline 2007. Apgar score less than 7 at five minutes, resuscitation at birth, admission to neonatal intensive care unit (NICU), seizure within first 24 hours of birth and meconium-stained amniotic fluid were the primary outcome measures to assess fetal asphyxia. Mode of delivery in each category, nuchal cord at birth were also assessed. Results: Majority of participants were in 25-to-29-year age group and were nulliparous. Frequencies of normal, suspicious and pathological CTG were 74.8%, 18% and 7.2% respectively. Pathological CTG was significantly associated with low Apgar score compared to non-pathological CTG group (p 0.005) while other outcome measures were not significant. Rate of operative delivery was 68% in pathological group and 20.8% in non-pathological CTG group. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of labour admission CTG to detect fetal asphyxia were 51.85%, 95.69%, 43.75% and 96.85% respectively. Conclusions: Incidence of pathological labour admission CTG was 7.2%. Apgar score less than 7 at five minutes of birth was significantly associated with pathological CTG group compared to non-pathological CTG (p 0.05). Worsening of CTG from normal to pathological showed increasing rate of operative delivery. Even though sensitivity and positive predictive values of labour admission CTG were low, specificity and negative predictive values were high for detecting low Apgar score. Therefore, labour admission CTG has a value in excluding adverse perinatal outcomes in low-risk term pregnancies in spontaneous labour.展开更多
Objective: To determine the reasons for admission of elderly subjects and the prognosis in general intensive care. Patients and Methods: Observational descriptive and analytical study with prospective collection of da...Objective: To determine the reasons for admission of elderly subjects and the prognosis in general intensive care. Patients and Methods: Observational descriptive and analytical study with prospective collection of data over a period of one year from January 1 to December 31, 2021. Patients aged 65 or over were included. Abstract: During the study period, 223 cases were collected out of 587 patients admitted, giving a prevalence of 37.9%. The average age was 74.127.39 ± years with extremes of 65 and 96 years and a male predominance (58.7%). The comorbidities were dominated by arterial hypertension (71.3%). The patients were: transferred from medical and surgical emergencies (75.8%). The average admission time was 48.8 ± 29.8 hours. One hundred and eight patients had a Glasgow score between 3 and 7. The reasons for admission were dominated by vascular causes (51.6%). Strokes of any type accounted for 43.9% of these reasons for admission. The average time for carrying out the biological assessments and imaging was 41.8 ± 27.3 hours with the extremes of 3 and 89 hours, 37.2% had a complete assessment within 24 hours. The average duration of hospitalization was 7.10 ± 8.87 days with extremes of 1 and 72 days. The mortality rate was 71.7%. Conclusion: This study has made it possible to take stock of the reasons for the admission of elderly subjects to intensive care. It appears that vascular causes are the main reasons for admission with heavy comorbidities which results in high mortality.展开更多
The robust admissibility analysis of a class of uncertain discrete-time switched linear singular（SLS） systems for arbitrary switching laws is addressed. The parameter uncertainty is assumed to be norm-bounded. First...The robust admissibility analysis of a class of uncertain discrete-time switched linear singular（SLS） systems for arbitrary switching laws is addressed. The parameter uncertainty is assumed to be norm-bounded. First, by using the switched Lyapunov function approach, some new sufficient conditions ensuring the nominal discrete-time SLS system to be regular, casual and asymptotically stable for arbitrary switching laws are derived in terms of linear matrix inequalities. Then, the robust admissibility condition for the uncertain discrete-time SLS systems is presented. The obtained results can be viewed as an extension of previous works on the switched Lyapunov function approach from the regular switched linear systems to the switched linear singular cases. Numerical examples show the reduced conservatism and effectiveness of the proposed conditions.展开更多
文摘The U.S.graduate admission system is a highly,if not the most,advanced system of its kind in the world.Much can be learned from this system and can be applied to improve other educational systems.This essay summarizes the components of the U.S.graduate admission process,analyzes the features of the system,and raises points of the U.S.system that might be helpful for improving China’s graduate admission system.
基金funded by International University,VNU-HCM under Grant Number T2020-03-IT.
文摘Question-Answer systems are now very popular and crucial to support human in automatically responding frequent questions in manyfields.However,these systems depend on learning methods and training data.Therefore,it is necessary to prepare such a good dataset,but it is not an easy job.An ontol-ogy-based domain knowledge base is able to help to reason semantic information and make effective answers given user questions.This study proposes a novel chatbot model involving ontology to generate efficient responses automatically.A case study of admissions advising at the International University–VNU HCMC is taken into account in the proposed chatbot.A domain ontology is designed and built based on the domain knowledge of university admissions using Protégé.The Web user interface of the proposed chatbot system is developed as a prototype using NetBeans.It includes a search engine reasoning the ontology and generat-ing answers to users’questions.Two experiments are carried out to test how the system reacts to different questions.Thefirst experiment examines questions made from some templates,and the second one examines normal questions taken from frequent questions.Experimental results have shown that the ontology-based chatbot can release meaningful and long answers.The results are analysed to prove the proposed chatbot is usable and promising.
文摘This study explores the effects of recent changes in China’s dance college admissions,which now equally weigh academic and professional performance.While the policy aims to create fairer admissions,it presents challenges for students from specialized dance programs(keban),who may struggle with academic demands.In contrast,academically strong students with limited dance training may gain an advantage.The research highlights the policy’s mixed impact and proposes flexible admissions strategies,such as conditional offers and ongoing academic support,to better accommodate students with diverse abilities.The study underscores the importance of refining these policies to ensure greater equity and cultural diversity in dance education.
文摘In this paper, a novel admission scheme is proposed which provides high degrees of quality of service (QoS) guarantees for multimedia traffic carried in mobile networks. The proposed scheme combines the admission control and bandwidth reservation to guarantee QoS requirements. It considers both local information and remote information to determine whether to accept or reject a connection. In order to embody the characteristics of the algorithms proposed in the article, two traditional algorithms of admission control are used for comparison. In the end of the paper the simulation analyses are given and the results show that the proposed algorithm can adjust the bandwidth according to the current status of networks and decrease the probability of connections forcibly dropped. The most important thing is that the algorithm is based on the multimedia communications and can guarantee the QoS of real time connections through decreasing the bandwidth of non real time connections.
文摘Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic of variable bit rate, so decreasing its bit rate can reduce the load of the system, consequently the system can admit new call which should be blocked when the system is close to full load, therefore new call＇s access probability increases. This paper brings forward design project and does system simulation, simulation proves that DCAC can effectively decrease calls＇ blocking probability and increase the total number of the on-line users.
基金supported by the Gong-Yi Program of China Meteorological Administration(GYHY201106034)National Natural Science Foundation of China(41075103)
文摘Air pollution has ever become a global major public health problem.Previous studies showed that air pollution is associated with excessive mortality and morbidity of respiratory disease[1-2].The extreme weather temperature can impact human health and the thermal stresses can lead not only to direct deaths and illnesses,but also to aggravation of respiratory disease[3-4].Though the independent
基金Supported by the National Natural Science Foundation of China (No. 61271421)the Education Department of Henan Province (No. 2011GGJS-002 and No. 12A510023)
文摘Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks. In this paper, we develop an executable top-down hierarchical Colored Petri Net (CPN) model for multi-traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system. By theoretic analysis and CPN simulation, it is demonstrated that the CPN model is isomorphic to Markov Chain (MC) assuming that each data stream follows Poisson distribution and the corresponding arrival time interval is an exponential random variable, and it breaks through MC's explicit limitation, which includes MC's memoryless property and proneness to state space explosion in evaluating CAC process. Moreover, we present four CAC schemes based on CPN model taking into account call-level and packet-level Quality of Service (QoS). The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performance with less computational complexity in addition to its flexibility and adaptability to different scenarios.
基金supported by the National Natural Science Foundation of China,Research on Brain Magnetic Resonance Image Segmentation Based on Particle Computation(No.61672386).
文摘Objective To evaluate the utility of computed tomography perfusion(CTP)both at admission and during delayed cerebral ischemia time-window(DCITW)in the detection of delayed cerebral ischemia(DCI)and the change in CTP parameters from admission to DCITW following aneurysmal subarachnoid hemorrhage.Methods Eighty patients underwent CTP at admission and during DCITW.The mean and extreme values of all CTP parameters at admission and during DCITW were compared between the DCI group and non-DCI group,and comparisons were also made between admission and DCITW within each group.The qualitative color-coded perfusion maps were recorded.Finally,the relationship between CTP parameters and DCI was assessed by receiver operating characteristic(ROC)analyses.Results With the exception of cerebral blood volume(P=0.295,admission;P=0.682,DCITW),there were significant differences in the mean quantitative CTP parameters between DCI and non-DCI patients both at admission and during DCITW.In the DCI group,the extreme parameters were significantly different between admission and DCITW.The DCI group also showed a deteriorative trend in the qualitative color-coded perfusion maps.For the detection of DCI,mean transit time to the center of the impulse response function(Tmax)at admission and mean time to start(TTS)during DCITW had the largest area under curve(AUC),0.698 and 0.789,respectively.Conclusion Whole-brain CTP can predict the occurrence of DCI at admission and diagnose DCI during DCITW.The extreme quantitative parameters and qualitative color-coded perfusion maps can better reflect the perfusion changes of patients with DCI from admission to DCITW.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 61001093)the National Basic Research Program of China (Grant No.2007CB310606)+1 种基金the Development Program for Outstanding Young Teachers in Harbin Institute of Technology (Grant No. HITQNJS. 2008. 063)the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(HIT. NSRIF. 2011114)
文摘Considering the advantage of interleave-division multiple-access(IDMA) technique and the technical bottlenecks in the existing satellite systems,IDMA is introduced into satellite communication networks.To further validate the IDMA into satellite systems,an effective call admission control(CAC) is proposed to maximize the resource utilization.After establishing the multi-beam satellite system model based on variable spreading gain(VSG) IDMA,the power allocation scheme based on SINR evolution technique and transmission rate adaptation for nonreal time interactive traffic are designed as integrated parts of the CAC,working together to improve the system performance in terms of power efficiency and throughput.Further,the analysis and simulation results show that IDMA under the proposed scheme can provide better QoS,in terms of the blocking/dropping probability,outage probability as well as delay performance.
文摘Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme.
基金This study was reviewed and approved by the Ethics Committee of The First Psychiatric Hospital of Harbin.
文摘BACKGROUND The literature has discussed the relationship between environmental factors and depressive disorders;however,the results are inconsistent in different studies and regions,as are the interaction effects between environmental factors.We hypo-thesized that meteorological factors and ambient air pollution individually affect and interact to affect depressive disorder morbidity.AIM To investigate the effects of meteorological factors and air pollution on depressive disorders,including their lagged effects and interactions.METHODS The samples were obtained from a class 3 hospital in Harbin,China.Daily hos-pital admission data for depressive disorders from January 1,2015 to December 31,2022 were obtained.Meteorological and air pollution data were also collected during the same period.Generalized additive models with quasi-Poisson regre-ssion were used for time-series modeling to measure the non-linear and delayed effects of environmental factors.We further incorporated each pair of environ-mental factors into a bivariate response surface model to examine the interaction effects on hospital admissions for depressive disorders.RESULTS Data for 2922 d were included in the study,with no missing values.The total number of depressive admissions was 83905.Medium to high correlations existed between environmental factors.Air temperature(AT)and wind speed(WS)significantly affected the number of admissions for depression.An extremely low temperature(-29.0℃)at lag 0 caused a 53%[relative risk(RR)=1.53,95%confidence interval(CI):1.23-1.89]increase in daily hospital admissions relative to the median temperature.Extremely low WSs(0.4 m/s)at lag 7 increased the number of admissions by 58%(RR=1.58,95%CI:1.07-2.31).In contrast,atmospheric pressure and relative humidity had smaller effects.Among the six air pollutants considered in the time-series model,nitrogen dioxide(NO_(2))was the only pollutant that showed significant effects over non-cumulative,cumulative,immediate,and lagged conditions.The cumulative effect of NO_(2) at lag 7 was 0.47%(RR=1.0047,95%CI:1.0024-1.0071).Interaction effects were found between AT and the five air pollutants,atmospheric temperature and the four air pollutants,WS and sulfur dioxide.CONCLUSION Meteorological factors and the air pollutant NO_(2) affect daily hospital admissions for depressive disorders,and interactions exist between meteorological factors and ambient air pollution.
文摘Among various radio sources which control different dependencies/functions, in this article, we will talk about the Call Admission Control (CAC), and we are supposed to confine our concentration on W-CDMA which is based on high raised platforms, since during the recent years remarkable amount of attention has been focused on platforms located in stratosphere layer [1]. Firstly, we study the capacity of uplink from HAP (High Altitude Platform) W-CDMA and we’ll work on estimation and power control defects in a new conversation added to current conversations. We’ll enhance the Call Admission Control (CAC) based on the side effects of power control defects and users’ stimulus and then compare the CAC which has been measured by using of momentary energy on bit in the spectral density form (Eb/N0). Then we examine the mentioned charts for two different criteria which the decision will be made by these criteria in order to decide if exchanged calls are to be admitted or not. The first criterion is based on the minimum of (Eb/N0) of the first row cells meanwhile the second criterion is based on the average of (Eb/N0) of first row-cells.
文摘This paper proposes the use of admission and traffic control schemes for real-time applications. The admission control scheme determines the admission of high-priority real-time applications such as voice and video streams in terms of their bandwidth utilization time (medium time), whereas the traffic control scheme maintains the communication quality of applications permitted admission by restricting other traffic. Owing to the use of contention-based access, a conventional scheme without admission control will degrade the communication quality when the number of terminals using high-priority applications increases. Moreover, only the capabilities (i.e., frame and sequence procedures) of admission control are defined in the IEEE 802.11e standard;the detailed usage in terms of the application characteristics is not specified, and it may be difficult to achieve a sufficient level of quality of service (QoS). The proposed schemes achieve the optimum QoS for actual services. The software used in the proposed schemes was implemented into hardware at the access point, and was evaluated experimentally. Based on the evaluation results, excellent performances with high QoS applications were obtained.
基金This work was supported in part by the Chongqing Technological Innovation and Application Development Projects under Grant cstc2019jscx-msxm1322,in part by the Zhejiang Lab under Grant 2021KF0AB03in part by the National Natural Science Foundation of China under Grant 62071091.
文摘Network slicing is envisioned as one of the key techniques to meet the extremely diversified service requirements of the Internet of Things(IoT)as it provides an enhanced user experience and elastic resource configuration.In the context of slicing enhanced IoT networks,both the Service Provider(SP)and Infrastructure Provider(InP)face challenges of ensuring efficient slice construction and high profit in dynamic environments.These challenges arise from randomly generated and departed slice requests from end-users,uncertain resource availability,and multidimensional resource allocation.Admission and resource allocation for distinct demands of slice requests are the key issues in addressing these challenges and should be handled effectively in dynamic environments.To this end,we propose an Opportunistic Admission and Resource allocation(OAR)policy to deal with the issues of random slicing requests,uncertain resource availability,and heterogeneous multi-resources.The key idea of OAR is to allow the SP to decide whether to accept slice requests immediately or defer them according to the load and price of resources.To cope with the random slice requests and uncertain resource availability,we formulated this issue as a Markov Decision Process(MDP)to obtain the optimal admission policy,with the aim of maximizing the system reward.Furthermore,the buyer-seller game theory approach was adopted to realize the optimal resource allocation,while motivating each SP and InP to maximize their rewards.Our numerical results show that the proposed OAR policy can make reasonable decisions effectively and steadily,and outperforms the baseline schemes in terms of the system reward.
基金supported by the ZTE Industry⁃University⁃Institute Cooperation Funds.
文摘Satellite communications has been regarded as an indispensable technology for future mobile networks to provide extremely high data rates,ultra-reliability,and ubiquitous coverage.However,the high dynamics caused by the fast movement of low-earth-orbit(LEO)satellites bring huge challenges in designing and optimizing satellite communication systems.Especially,admission control,deciding which users with diversified service requirements are allowed to access the network with limited resources,is of paramount importance to improve network resource utilization and meet the service quality requirements of users.In this paper,we propose a dynamic channel reservation strategy based on the Actor-Critic algorithm(AC-DCRS)to perform intelligent admission control in satellite networks.By carefully designing the longterm reward function and dynamically adjusting the reserved channel threshold,AC-DCRS reaches a long-run optimal access policy for both new calls and handover calls with different service priorities.Numerical results show that our proposed AC-DCRS outperforms traditional channel reservation strategies in terms of overall access failure probability,the average call success rate,and channel utilization under various dynamic traffic conditions.
文摘BACKGROUND. The intensive care unit provides critically ill patients with the necessary monitoring, care and supports to optimize their organ/system functions. Parturients are often at risk of sudden deteriorations or exacerbation of chronic illnesses from direct or indirect causes and would often require admissions into the intensive care or high dependency unit. This study is aimed at looking at the trends of maternal admissions in 365 days at the intensive care unit of a tertiary teaching hospital in Southern part of Nigeria, a country that contributes significantly to the global proportion of maternal morbidity and mortality. METHODS. The study adopted a retrospective approach. All critically ill parturients admitted and requiring organ support or close monitoring in the ICU had their files and ICU documents reviewed. The review was held from January-December 2018. RESULTS. Thirty-nine (39) parturients with a mean age (years) of 33 ± 1.3 were admitted, representing 2.9% of annual deliveries. All admissions were postnatal and came predominantly from the unbooked labour ward (51%) and the time lag from maternal deteriorations to presentation to the ICU was 72 ± 10 hours. The main indications for admissions were due to postpartum haemorrhage (33.3%), complications of hypertensive disorders of pregnancy (30.9%) and sepsis (25.6%). Nineteen (48.7%) patients died from obstetric haemorrhage, complications of hypertensive disorders of pregnancy, sepsis and pulmonary embolism. CONCLUSION. The trend of maternal admissions at this specific time frame reflects the burden of maternal critical care in our environment. It highlights the need to holistically tackle the known scourge with improved care.
文摘Objective:To explore the effects of daily mean temperature(°C),average daily air pressure(hPa),humidity(%),wind speed(m/s),particulate matter(PM)2.5(μg/m3)and PM10(μg/m3)on the admission rate of chronic kidney disease(CKD)patients admitted to the Second Affiliated Hospital of Harbin Medical University in Harbin and to identify the indexes and lag days that impose the most critical influence.Methods:The R language Distributed Lag Nonlinear Model(DLNM),Excel,and SPSS were used to analyze the disease and meteorological data of Harbin from 01 January 2010 to 31 December 2019 according to the inclusion and exclusion criteria.Results:Meteorological factors and air pollution influence the number of hospitalizations of CKD to vary degrees in cold regions,and differ in persistence or delay.Non-optimal temperature increases the risk of admission of CKD,high temperature increases the risk of obstructive kidney disease,and low temperature increases the risk of other major types of chronic kidney disease.The greater the temperature difference is,the higher its contribution is to the risk.The non-optimal wind speed and non-optimal atmospheric pressure are associated with increased hospital admissions.PM2.5 concentrations above 40μg/m3 have a negative impact on the results.Conclusion:Cold region meteorology and specific environment do have an impact on the number of hospital admissions for chronic kidney disease,and we can apply DLMN to describe the analysis.
文摘Introduction: Labour admission cardiotocography (CTG) is commonly used non-invasive method of fetal monitoring in Sri Lanka. It may have a potentialto predict perinatal outcome in low-risk term pregnancies. Objectives: Objectives of the study were to determine the perinatal outcomes of normal, suspicious and pathological admission CTGs and role of labour admission cardiotocography as a predictive test for perinatal outcome in low-risk term pregnancies in spontaneous labour. Methods: This study was a prospective observational study done involving 445 low risk, term pregnancies in spontaneous labour. Labour admission CTG was performed in each pregnancy and categorized into normal, suspicious and pathological CTG according to criteria depicted by National Institute of Clinical Excellence (NICE) guideline 2007. Apgar score less than 7 at five minutes, resuscitation at birth, admission to neonatal intensive care unit (NICU), seizure within first 24 hours of birth and meconium-stained amniotic fluid were the primary outcome measures to assess fetal asphyxia. Mode of delivery in each category, nuchal cord at birth were also assessed. Results: Majority of participants were in 25-to-29-year age group and were nulliparous. Frequencies of normal, suspicious and pathological CTG were 74.8%, 18% and 7.2% respectively. Pathological CTG was significantly associated with low Apgar score compared to non-pathological CTG group (p 0.005) while other outcome measures were not significant. Rate of operative delivery was 68% in pathological group and 20.8% in non-pathological CTG group. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of labour admission CTG to detect fetal asphyxia were 51.85%, 95.69%, 43.75% and 96.85% respectively. Conclusions: Incidence of pathological labour admission CTG was 7.2%. Apgar score less than 7 at five minutes of birth was significantly associated with pathological CTG group compared to non-pathological CTG (p 0.05). Worsening of CTG from normal to pathological showed increasing rate of operative delivery. Even though sensitivity and positive predictive values of labour admission CTG were low, specificity and negative predictive values were high for detecting low Apgar score. Therefore, labour admission CTG has a value in excluding adverse perinatal outcomes in low-risk term pregnancies in spontaneous labour.
文摘Objective: To determine the reasons for admission of elderly subjects and the prognosis in general intensive care. Patients and Methods: Observational descriptive and analytical study with prospective collection of data over a period of one year from January 1 to December 31, 2021. Patients aged 65 or over were included. Abstract: During the study period, 223 cases were collected out of 587 patients admitted, giving a prevalence of 37.9%. The average age was 74.127.39 ± years with extremes of 65 and 96 years and a male predominance (58.7%). The comorbidities were dominated by arterial hypertension (71.3%). The patients were: transferred from medical and surgical emergencies (75.8%). The average admission time was 48.8 ± 29.8 hours. One hundred and eight patients had a Glasgow score between 3 and 7. The reasons for admission were dominated by vascular causes (51.6%). Strokes of any type accounted for 43.9% of these reasons for admission. The average time for carrying out the biological assessments and imaging was 41.8 ± 27.3 hours with the extremes of 3 and 89 hours, 37.2% had a complete assessment within 24 hours. The average duration of hospitalization was 7.10 ± 8.87 days with extremes of 1 and 72 days. The mortality rate was 71.7%. Conclusion: This study has made it possible to take stock of the reasons for the admission of elderly subjects to intensive care. It appears that vascular causes are the main reasons for admission with heavy comorbidities which results in high mortality.
基金The National Natural Science Foundation of China(No.60835001)the Key Project of Ministry of Education of China (No.108060)
文摘The robust admissibility analysis of a class of uncertain discrete-time switched linear singular（SLS） systems for arbitrary switching laws is addressed. The parameter uncertainty is assumed to be norm-bounded. First, by using the switched Lyapunov function approach, some new sufficient conditions ensuring the nominal discrete-time SLS system to be regular, casual and asymptotically stable for arbitrary switching laws are derived in terms of linear matrix inequalities. Then, the robust admissibility condition for the uncertain discrete-time SLS systems is presented. The obtained results can be viewed as an extension of previous works on the switched Lyapunov function approach from the regular switched linear systems to the switched linear singular cases. Numerical examples show the reduced conservatism and effectiveness of the proposed conditions.
