Orthogonal time frequency space(OTFS)modulation has been proven to be superior to traditional orthogonal frequency division multiplexing(OFDM)systems in high-speed communication scenarios.However,the existing channel ...Orthogonal time frequency space(OTFS)modulation has been proven to be superior to traditional orthogonal frequency division multiplexing(OFDM)systems in high-speed communication scenarios.However,the existing channel estimation schemes may results in poor peak to average power ratio(PAPR)performance of OTFS system or low spectrum efficiency.Hence,in this paper,we propose a low PAPR channel estimation scheme with high spectrum efficiency.Specifically,we design a multiple scattered pilot pattern,where multiple low power pilot symbols are superimposed with data symbols in delay-Doppler domain.Furthermore,we propose the placement rules for pilot symbols,which can guarantee the low PAPR.Moreover,the data aided iterative channel estimation was invoked,where joint channel estimation is proposed by exploiting multiple independent received signals instead of only one received signal in the existing scheme,which can mitigate the interference imposed by data symbols for channel estimation.Simulation results shows that the proposed multiple scattered pilot aided channel estimation scheme can significantly reduce the PAPR while keeping the high spectrum efficiency.展开更多
Indicators based on the developed version of the Capability Maturity Model were set up to access the maturity degree of China's seven pilot carbon markets from 2013 to 2017. Results show that the maturity degree o...Indicators based on the developed version of the Capability Maturity Model were set up to access the maturity degree of China's seven pilot carbon markets from 2013 to 2017. Results show that the maturity degree of Shenzhen and Beijing pilot carbon markets ranks first;while those of Guangdong, Hubei, and Shanghai rank second. Tianjin and Chongqing rank lowest. Most of pilot markets failed to perform well on price efficiency except Shenzhen. There is significant disparity in the scores that the pilot carbon markets got, with a range from 9 to 73. The drivers to maintain market maturity is different among the pilot markets, either with a good performance on market structure, scale, or efficiency could lead to a certain score. Much could be done to increase the maturity level of the carbon market. Further downscaling the firm size, raising the legislation level, and increasing the participation of the third party entities may help the carbon market to grow healthier.展开更多
In this paper,the spectral efficiency(SE)of an uplink hardware-constrained cell-free massive multi-input multi-output(MIMO)system with maximal ratio combining(MRC)receiver filters in the context of superimposed pilots...In this paper,the spectral efficiency(SE)of an uplink hardware-constrained cell-free massive multi-input multi-output(MIMO)system with maximal ratio combining(MRC)receiver filters in the context of superimposed pilots(SPs)is investigated.Tractable closed-form SE expressions for the considered system are derived,which share us with opportunities to explore the impacts of the hardware quality coefficient,the length of coherence interval,and the power balance factor between pilot and data signals.Numerical results indicate that the achievable SE deteriorates as the hardware quality decreases and is more susceptible to the hardware impairments at the user equipments(UEs).Besides,we observe that SPs outperform regular pilots(RPs)in terms of SE and this performance gain is heavily dependent on the values of power balance factor and coherence interval.However,the superiorities of SPs over RPs have vanished when severe hardware imperfections are considered.展开更多
BACKGROUND Recently,two naval pilots in a two-seat trainer jet were forced to eject urgently due to sudden mechanical failure during night-time training.They were both successfully rescued and sent to the hospital for...BACKGROUND Recently,two naval pilots in a two-seat trainer jet were forced to eject urgently due to sudden mechanical failure during night-time training.They were both successfully rescued and sent to the hospital for emergency treatment.In this study,we investigate their ejection injuries and recovery process.CASE SUMMARY We analyzed the clinical data of the traumatic condition and recovery process from ejection injuries of two pilots who ejected from a failed trainer jet and survived.After being successfully rescued and sent to the hospital,they were diagnosed with multiple ejection injuries,including eye trauma,limb bone and joint injury,rib and spine injury,and so on.Both cases underwent fluid replacement,acid suppression,nutritional support,hemostasis,bone metabolism improvement,phlegm elimination,psychological measurement,blood circulation promotion and detumescence,physical therapy,and external fixation with braces for 1 mo before being discharged from hospital.They then recuperated in a sanatorium for 2 mo,and the related laboratory tests and supplementary examinations show that they recovered from all the above injuries.After successfully passing the psychological test and physical examination,they returned to flight duty 3 mo after ejection.CONCLUSION The causes and conditions of ejection injury in the pilots were very complex.Although they finally recovered quickly and were released,it also serves as a reminder that attention should be paid to pilots’ejection and parachute training in order to significantly reduce ejection injury and improve the ejection success rate.In addition,air defense support personnel should strengthen search and rescue and on-site emergency measures,and locate and rescue pilots in distress as early as possible to reduce subsequent injuries.展开更多
Pilot is one of the most important factors to ensure aviation safety. The article focuses on the Pilots Development Planning (PDP) problem. It is different from other countries that pilots are developed by airways the...Pilot is one of the most important factors to ensure aviation safety. The article focuses on the Pilots Development Planning (PDP) problem. It is different from other countries that pilots are developed by airways themselves in China. Promotion of every pilot needs specified quantity of flight experience hours which are accumulated in daily flights. In the same time, the promotion routes of pilots are diversified. So keys of PDP problem are to estimate the number of pilots who have promotion qualification in different planning period and to optimize their promotion and transfer in all routes. After analyzing characteristics of pilot training, a PDP road map is drawn which shows the typical process for pilots’ promotion and transfer. An optimization model which has promotion qualification constraints is built to solve PDP problem. According to different pilot development patterns, the method is proved to be effectively by a case study. The research has practical significance for Chinese airways.展开更多
On December 7.1993,as|soon as an airplane landed at the Uhasa airport,sever-al Americans dashed down from it.Burning with impatience,they were in no mood to enjoy the wonderful scenery in this city on the heights,but ...On December 7.1993,as|soon as an airplane landed at the Uhasa airport,sever-al Americans dashed down from it.Burning with impatience,they were in no mood to enjoy the wonderful scenery in this city on the heights,but asked in haste,"Where?Where ane they?"展开更多
Prior to the 60th anniversary of founding of People’s Republic of China that marks calendar day of Oct.1st this year, Chinese armed forces stage on a new change of uniforms to welcome the birthday of the New China th...Prior to the 60th anniversary of founding of People’s Republic of China that marks calendar day of Oct.1st this year, Chinese armed forces stage on a new change of uniforms to welcome the birthday of the New China that was展开更多
BACKGROUND Colorectal cancer(CRC)could seriously threaten the physical and mental health of pilots.Shall they end their flying after treatment of CRC?With this study,we investigated the possibility of a gradual medica...BACKGROUND Colorectal cancer(CRC)could seriously threaten the physical and mental health of pilots.Shall they end their flying after treatment of CRC?With this study,we investigated the possibility of a gradual medical waiver for such pilots to fly aircrafts again after treatment of CRC.CASE SUMMARY We analyzed the medical waiver and clinical data of 3 pilots with CRC,who had accepted the treatment at the Department of General Surgery,Air Force Medical Center(formerly,Air Force General Hospital)between 2013 and 2018.All 3 cases underwent a series of comprehensive treatment courses,including radical resection of CRC,sequential radiotherapy,and chemotherapy.The follow-up results were satisfactory.After passing through the high-risk period of recurrence and metastasis of CRC,they all were given a medical waiver for flying again.Medical observation showed that their flying operations were safe.CONCLUSION The CRC treatment shall follow the guidelines for diagnosis and treatment and should simultaneously protect the combating capabilities of pilots as much as possible.It is safe for pilots with CRC,who are continuously monitored under medical observation after passing through the high-risk period of recurrence and metastasis,to undertake military flight missions again.展开更多
Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver. Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI. Use of pilot...Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver. Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI. Use of pilot symbols for channel estimation, introduces overhead and it is desirable to keep the number of pilot symbols as minimum as possible. This paper introduces a new tight bound for the number of pilots in channel estimation using adaptive scheme in OFDM systems. We calculate the minimum number of necessary pilots using two approaches. The first approach for the number of pilots is obtained based on Doppler frequency shift estimation and the second approach is acquired based on channel length estimation using second order statistics of received signal. Finally we obtain the tight bound for the number of pilots using attained values.展开更多
This paper analyzes the three main fundamental issues in the design of China's ETS pilots,including allowance allocation,price mechanism and state-owned key enterprises,and proposed suggested solutions.For the iss...This paper analyzes the three main fundamental issues in the design of China's ETS pilots,including allowance allocation,price mechanism and state-owned key enterprises,and proposed suggested solutions.For the issue of allowance allocation,we suggest that the gradual hybrid mode could be applied at the beginning,which starts with mainly free allocation and then increases auction ratio gradually.And grandfathering is a suitable method of free allocation.For the issue of price mechanism,we suggest a price floating zone with open market operation to reduce the uncertainty of prices.For the issue of state-owned key enterprises,we suggest a good coordination with SASAC,defining the state-owned property right and supervision right when state-owned key enterprises are involved into the carbon market,and the local government can set rules of allocation and transaction to limit their potential market power.展开更多
Comparison in the heart rate, oral temperature and lymphocyte DNAdamage during heat stress was made in pilots with negative antibodies to heatstress proteins (HSPs) and those with positive antibodies in the man-made c...Comparison in the heart rate, oral temperature and lymphocyte DNAdamage during heat stress was made in pilots with negative antibodies to heatstress proteins (HSPs) and those with positive antibodies in the man-made climate room with Western blot and comet assay. Our results showed that the increase in oral temperature, heart rate and lymphocyte DNA damage in pilots with the posi-tive antibodies to HSPs were higher than those in pilots with the negative antibod-ies during heat stress. These results indicated that the presence of autoantibodies in plasma of pilots might reflect heat damage and high sensitivity to heat.展开更多
ECGs of 3 565 clinically normal male pilots,aged from 21 to 51 years,were classi-fied and analyzed by Minnesota code.Among the 3 565 pilots,there were 1 315 coded pilots,making up 36.89％ of the total number.The resul...ECGs of 3 565 clinically normal male pilots,aged from 21 to 51 years,were classi-fied and analyzed by Minnesota code.Among the 3 565 pilots,there were 1 315 coded pilots,making up 36.89％ of the total number.The results were as follows:abnormal Q/QS wave0.14％,electrocardial axis deflection 5.11％,high voltage of left ventricle 10.58％,chargedST-T segment 2.07％,atrioventricular conduction block 1.71％,intraventricular conductionblock 4.60％,arrhytmias 10.66％ and other abnormalities 13.04％.The research showed thatthere were various changes in the coded pilots,although no abnormal alteration of the cardio-vascular system was discovered by physical examination,the ECG exercise stress test and otherrelevant clinical tests.This suggests that most of ECG abnormalities in clinically normal pilotsare normal physiological and functional variations.展开更多
BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of sp...BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of specific pulmonary infections in naval pilots.CASE SUMMARY We analyzed the medical waiver and clinical data of four pilots with specific pulmonary infections,who had accepted treatment at the Naval Medical Center of Chinese People’s Liberation Army between January 2020 and November 2021,including three cases of tuberculosis and one of cryptococcal pneumonia.All cases underwent a series of comprehensive treatment courses.Three cases successfully obtained medical waiver for flight after being cured,while one was grounded after reaching the maximum flight life after being cured.CONCLUSION Chest computed tomography scanning should be used instead of chest radiography in pilots’physical examination.Most pilots with specific pulmonary infection can be cured and return to flight.展开更多
This study aims to explore dimensions of quality of work life (QWL) of pilots by using an exploratory factor analysis (EFA). The sample was 400 pilots who are currently working for an airline based in Thailand. The it...This study aims to explore dimensions of quality of work life (QWL) of pilots by using an exploratory factor analysis (EFA). The sample was 400 pilots who are currently working for an airline based in Thailand. The items using in this study were generated using input from three sources. First, using input from commercial pilots who had a minimum of total 5,000 flying hour and currently working for either premium or low cost airlines in Thailand. Second, translated quality of work life items from a published research on Quality of Work Life of Personnel at Dhurakij Pundit University by Chatthai (2016). After the content analysis, the left items for the EFA analysis were 30 items. The Kaiser-Meyer-Olkin (KMO) demonstrated at 0.93. The exploratory factor analysis was to examine the loading patterns of QWL items. A principal component and orthogonal rotation (Verimax method) were chosen. It showed there were five structural factor patterns. The five factors were labored as “Human Resource Management”;“Social Relation”;“Safe Working Environment”;“Work-Life Balance”;and “Fairness and Respect”. Discussion and future research are also discussed.展开更多
In wireless orthogonal frequency division multiplexing (OFDM) systems, the time-varying channel is often estimated by algorithms based on pilot symbols. Such an estimator, however, requires statistical prior knowledge...In wireless orthogonal frequency division multiplexing (OFDM) systems, the time-varying channel is often estimated by algorithms based on pilot symbols. Such an estimator, however, requires statistical prior knowledge that is not easily obtained. Therefore, the pilot tones have to be close enough to fulfill the sampling theorem. In this case the statistical knowledge of the channel is not required to reconstruct correctly the channel impulse response (CIR). This paper explores the optimal placement and number of pilot symbols, we investigate optimal training sequences in OFDM systems and we analyze the number of pilot symbols required to fulfill the sampling theorem. Using a general model for a multipath slowly fading channel, the approach is based on the LS as a criterion of channel estimation while the channel interpolation is done using the piecewise-constant interpolation compromising between complexity and performance. Simulation results demonstrate the good performance of our approach.展开更多
With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even elimina...With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular line-of-sight.At the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance command.The proposed system’s stability is proven based on the Lyapunov stability criterion.The simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance laws.Furthermore,ISMGL has a more accurate impact angle and fast convergence speed.展开更多
Background: Cervical Intraepithelial neoplasia treatments have become essential interventions to manage cervical lesions. Majority of the recipients of these treatments are women within the reproductive age group, who...Background: Cervical Intraepithelial neoplasia treatments have become essential interventions to manage cervical lesions. Majority of the recipients of these treatments are women within the reproductive age group, who according to literature may be at risk of adverse pregnancy outcomes. This pilot study is part of a study investigating adverse pregnancy outcomes among women who received Cryotherapy, Thermal ablation and Loop Electrosurgical Excision Procedure compared to the untreated women in Zambia. Materials and Methods: This descriptive study analyzed records of 886 (n = 443 treated and n = 443 untreated) women aged 15 - 49 years. The women were either screened with Visual Inspection with Acetic Acid or treated for Cervical Intraepithelial neoplasia at the Adult Infectious Disease Centre between January 2010 and December 2020. Women meeting the criteria were identified using the Visual Inspection with Acetic Acid screening records and telephone interviews to obtain the adverse pregnancy outcome experienced. Data were analysed using STATA version 16 to determine the prevalence and obtain frequency distribution of outcomes of interest. Univariate and multivariable binary logistic regression estimated odds of adverse pregnancy outcomes across the three treatments. Results: The respondents were aged 15 to 49 years. Adverse pregnancy outcomes were observed to be more prevalent in the treatment group (18.5%) compared to the untreated group (5.4%). Normal pregnancy outcomes were lower in the treated (46.3%;n = 443) than the untreated (53.7%;n = 443). The treated group accounted for the majority of abortions (85.2%), prolonged labour (85.7%) and low birth weight (80%), whereas, the untreated accounted for the majority of still births (72.7%). Women treated with cryotherapy (aOR = 2.43, 95% CI = 1.32 - 4.49, p = 0.004), thermal ablation (aOR = 6.37, 95% CI = 0.99 - 41.2, p = 0.052) and Loop Electrosurgical Excision Procedure (aOR = 9.67, 95% CI = 2.17 - 43.1, p = 0.003) had two-, six- and ten-times higher odds of adverse pregnancy outcomes respectively, relative to women who required no treatment. Conclusion: Adverse pregnancy outcomes are prevalent among women who have received treatment in Zambia. The findings indicate that treating Cervical Intraepithelial Neoplasia has been linked to higher chances of experiencing abortion, delivering low birth weight babies and enduring prolonged labor that may result in a caesarean section delivery. Cervical neoplasia treatments, particularly Loop Electrosurgical Excision Procedure, are associated with significantly increased odds of adverse pregnancy outcomes. It is essential to include information about prior Cervical Intraepithelial neoplasia treatment outcomes in obstetric care.展开更多
On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Ha...On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according展开更多
This study explored the use of multi-physiological signals and simultaneously recorded high-density electroencephalography(EEG),electrocardiogram(ECG),and eye movements to better understand pilots’cognitive behaviour...This study explored the use of multi-physiological signals and simultaneously recorded high-density electroencephalography(EEG),electrocardiogram(ECG),and eye movements to better understand pilots’cognitive behaviour during flight simulator manoeuvres.Multimodal physiological signals were collected from 12 experienced pilots with international aviation qualifications under the wide-angle and impressive vision simulation.The data collection spanned two flight strike missions,each with three mission intensities,resulting in a data set of EEG,ECG,and eye movement signals from six subtasks.The multimodal data were analysed using signal processing methods.The results indicated that,when the flight missions were performed,the pilots’physiological characteristics exhibited rhythmic changes in the power spectrum ofθwaves in the EEG,r-MSSD in the ECG,and average gaze duration.Furthermore,the pilots’physiological signals were more sensitive during the target mission than during the empty target mission.The results also showed correlations between different physiological characteristics.We showed that specific multimodal features are useful for advancing neuroscience research into pilots’cognitive behaviour and processes related to brain activity,psychological rhythms,and eye movement.展开更多
裂隙介质渗透结构表现为高度的非均质性与各项异性。为了科学有效地预测某核工程场地裂隙地下水的流动规律,揭示裂隙岩体地下水的渗流特性,笔者等采用Pilot Point调参方法与null space Monte Carlo方法(NSMC),开展了裂隙岩体渗透结构的...裂隙介质渗透结构表现为高度的非均质性与各项异性。为了科学有效地预测某核工程场地裂隙地下水的流动规律,揭示裂隙岩体地下水的渗流特性,笔者等采用Pilot Point调参方法与null space Monte Carlo方法(NSMC),开展了裂隙岩体渗透结构的不确定性分析研究,构建了符合实际水文地质条件的多个渗流数值模型集合。结果表明:该方法获得的各个实现地下水位模拟结果能够与实际观测数据较好吻合,可反映工程场地裂隙地下水动力特征与流动趋势;各个实现的参数化渗透结构在空间上存在一定的差异性,但整体变化趋势是保持一致的,渗透参数的不确定性表现为在实测数据分布区域相对较低,钻孔空白区域相对较高;该方法可以弥补单一、确定性模拟结果在表征裂隙介质渗透结构方面的局限性,有效地降低模型参数的不确定性与随机性。此方法对进一步提升裂隙岩体渗流模拟精度与预测能力,深化裂隙地下水迁移规律的认识具有重要的意义。展开更多
基金supported by National Natural Science Foundation of China(No.61871452)。
文摘Orthogonal time frequency space(OTFS)modulation has been proven to be superior to traditional orthogonal frequency division multiplexing(OFDM)systems in high-speed communication scenarios.However,the existing channel estimation schemes may results in poor peak to average power ratio(PAPR)performance of OTFS system or low spectrum efficiency.Hence,in this paper,we propose a low PAPR channel estimation scheme with high spectrum efficiency.Specifically,we design a multiple scattered pilot pattern,where multiple low power pilot symbols are superimposed with data symbols in delay-Doppler domain.Furthermore,we propose the placement rules for pilot symbols,which can guarantee the low PAPR.Moreover,the data aided iterative channel estimation was invoked,where joint channel estimation is proposed by exploiting multiple independent received signals instead of only one received signal in the existing scheme,which can mitigate the interference imposed by data symbols for channel estimation.Simulation results shows that the proposed multiple scattered pilot aided channel estimation scheme can significantly reduce the PAPR while keeping the high spectrum efficiency.
基金We thank Miss DENG Ying-Ying for data collection. This work was funded by the National Key Research and Devel opment Program of China (2018YFC1509008) and the Na tional Natural Science Foundation of China (41401058).
文摘Indicators based on the developed version of the Capability Maturity Model were set up to access the maturity degree of China's seven pilot carbon markets from 2013 to 2017. Results show that the maturity degree of Shenzhen and Beijing pilot carbon markets ranks first;while those of Guangdong, Hubei, and Shanghai rank second. Tianjin and Chongqing rank lowest. Most of pilot markets failed to perform well on price efficiency except Shenzhen. There is significant disparity in the scores that the pilot carbon markets got, with a range from 9 to 73. The drivers to maintain market maturity is different among the pilot markets, either with a good performance on market structure, scale, or efficiency could lead to a certain score. Much could be done to increase the maturity level of the carbon market. Further downscaling the firm size, raising the legislation level, and increasing the participation of the third party entities may help the carbon market to grow healthier.
基金This work was supported in part by the National Natural Science Foundation of China under Grants 62071246,61771252,61861039,and 61427801in part by the National Key Research and Development Program of China under Grants 2020YFB1806608 and 2018YFC1314903+2 种基金in part by the Jiangsu Province Special Fund Project for Transformation of Scientific and Technological Achievements under Grant BA2019058in part by the Major Natural Science Research Project of Jiangsu Higher Education Institutions under Grant 18KJA510005in part by the Postgraduate Research&Practice Innovation Program of Jiangsu Province under Grants SJKY190740 and KYCX200709.
文摘In this paper,the spectral efficiency(SE)of an uplink hardware-constrained cell-free massive multi-input multi-output(MIMO)system with maximal ratio combining(MRC)receiver filters in the context of superimposed pilots(SPs)is investigated.Tractable closed-form SE expressions for the considered system are derived,which share us with opportunities to explore the impacts of the hardware quality coefficient,the length of coherence interval,and the power balance factor between pilot and data signals.Numerical results indicate that the achievable SE deteriorates as the hardware quality decreases and is more susceptible to the hardware impairments at the user equipments(UEs).Besides,we observe that SPs outperform regular pilots(RPs)in terms of SE and this performance gain is heavily dependent on the values of power balance factor and coherence interval.However,the superiorities of SPs over RPs have vanished when severe hardware imperfections are considered.
基金Supported by Key Projects of Medical Service Scientific Research of the Navy Medical Center,No.20M2302.
文摘BACKGROUND Recently,two naval pilots in a two-seat trainer jet were forced to eject urgently due to sudden mechanical failure during night-time training.They were both successfully rescued and sent to the hospital for emergency treatment.In this study,we investigate their ejection injuries and recovery process.CASE SUMMARY We analyzed the clinical data of the traumatic condition and recovery process from ejection injuries of two pilots who ejected from a failed trainer jet and survived.After being successfully rescued and sent to the hospital,they were diagnosed with multiple ejection injuries,including eye trauma,limb bone and joint injury,rib and spine injury,and so on.Both cases underwent fluid replacement,acid suppression,nutritional support,hemostasis,bone metabolism improvement,phlegm elimination,psychological measurement,blood circulation promotion and detumescence,physical therapy,and external fixation with braces for 1 mo before being discharged from hospital.They then recuperated in a sanatorium for 2 mo,and the related laboratory tests and supplementary examinations show that they recovered from all the above injuries.After successfully passing the psychological test and physical examination,they returned to flight duty 3 mo after ejection.CONCLUSION The causes and conditions of ejection injury in the pilots were very complex.Although they finally recovered quickly and were released,it also serves as a reminder that attention should be paid to pilots’ejection and parachute training in order to significantly reduce ejection injury and improve the ejection success rate.In addition,air defense support personnel should strengthen search and rescue and on-site emergency measures,and locate and rescue pilots in distress as early as possible to reduce subsequent injuries.
文摘Pilot is one of the most important factors to ensure aviation safety. The article focuses on the Pilots Development Planning (PDP) problem. It is different from other countries that pilots are developed by airways themselves in China. Promotion of every pilot needs specified quantity of flight experience hours which are accumulated in daily flights. In the same time, the promotion routes of pilots are diversified. So keys of PDP problem are to estimate the number of pilots who have promotion qualification in different planning period and to optimize their promotion and transfer in all routes. After analyzing characteristics of pilot training, a PDP road map is drawn which shows the typical process for pilots’ promotion and transfer. An optimization model which has promotion qualification constraints is built to solve PDP problem. According to different pilot development patterns, the method is proved to be effectively by a case study. The research has practical significance for Chinese airways.
文摘On December 7.1993,as|soon as an airplane landed at the Uhasa airport,sever-al Americans dashed down from it.Burning with impatience,they were in no mood to enjoy the wonderful scenery in this city on the heights,but asked in haste,"Where?Where ane they?"
文摘Prior to the 60th anniversary of founding of People’s Republic of China that marks calendar day of Oct.1st this year, Chinese armed forces stage on a new change of uniforms to welcome the birthday of the New China that was
基金Supported by Major Projects of the Chinese PLA “Thirteenth Five-Year Plan”Logistics Research Subject,No.AKJ15J003 and No.AKJ15J001Incubation Project of Military Medical Science and Technology Youth Cultivation Program,No.17QNP023
文摘BACKGROUND Colorectal cancer(CRC)could seriously threaten the physical and mental health of pilots.Shall they end their flying after treatment of CRC?With this study,we investigated the possibility of a gradual medical waiver for such pilots to fly aircrafts again after treatment of CRC.CASE SUMMARY We analyzed the medical waiver and clinical data of 3 pilots with CRC,who had accepted the treatment at the Department of General Surgery,Air Force Medical Center(formerly,Air Force General Hospital)between 2013 and 2018.All 3 cases underwent a series of comprehensive treatment courses,including radical resection of CRC,sequential radiotherapy,and chemotherapy.The follow-up results were satisfactory.After passing through the high-risk period of recurrence and metastasis of CRC,they all were given a medical waiver for flying again.Medical observation showed that their flying operations were safe.CONCLUSION The CRC treatment shall follow the guidelines for diagnosis and treatment and should simultaneously protect the combating capabilities of pilots as much as possible.It is safe for pilots with CRC,who are continuously monitored under medical observation after passing through the high-risk period of recurrence and metastasis,to undertake military flight missions again.
文摘Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver. Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI. Use of pilot symbols for channel estimation, introduces overhead and it is desirable to keep the number of pilot symbols as minimum as possible. This paper introduces a new tight bound for the number of pilots in channel estimation using adaptive scheme in OFDM systems. We calculate the minimum number of necessary pilots using two approaches. The first approach for the number of pilots is obtained based on Doppler frequency shift estimation and the second approach is acquired based on channel length estimation using second order statistics of received signal. Finally we obtain the tight bound for the number of pilots using attained values.
基金supported by Asian CORE program"Manufacturing and Environmental Management in East Asia" of the Japan Society for the Promotion of Science(JSPS)supported by the 2010 Key Project of Philosophy and Social Sciences Research,Ministry of Education:"Research on China's Emissions Trading System under Low-carbon Economy Transformation"(Grant No.10JZD0018)+1 种基金the New Century Excellent Talents Support Plan,Ministry of Education(Grant No.NCET-10-0646)the Key Project of the National Social Science Foundation of China(Grant No.12&ZD059)
文摘This paper analyzes the three main fundamental issues in the design of China's ETS pilots,including allowance allocation,price mechanism and state-owned key enterprises,and proposed suggested solutions.For the issue of allowance allocation,we suggest that the gradual hybrid mode could be applied at the beginning,which starts with mainly free allocation and then increases auction ratio gradually.And grandfathering is a suitable method of free allocation.For the issue of price mechanism,we suggest a price floating zone with open market operation to reduce the uncertainty of prices.For the issue of state-owned key enterprises,we suggest a good coordination with SASAC,defining the state-owned property right and supervision right when state-owned key enterprises are involved into the carbon market,and the local government can set rules of allocation and transaction to limit their potential market power.
文摘Comparison in the heart rate, oral temperature and lymphocyte DNAdamage during heat stress was made in pilots with negative antibodies to heatstress proteins (HSPs) and those with positive antibodies in the man-made climate room with Western blot and comet assay. Our results showed that the increase in oral temperature, heart rate and lymphocyte DNA damage in pilots with the posi-tive antibodies to HSPs were higher than those in pilots with the negative antibod-ies during heat stress. These results indicated that the presence of autoantibodies in plasma of pilots might reflect heat damage and high sensitivity to heat.
文摘ECGs of 3 565 clinically normal male pilots,aged from 21 to 51 years,were classi-fied and analyzed by Minnesota code.Among the 3 565 pilots,there were 1 315 coded pilots,making up 36.89％ of the total number.The results were as follows:abnormal Q/QS wave0.14％,electrocardial axis deflection 5.11％,high voltage of left ventricle 10.58％,chargedST-T segment 2.07％,atrioventricular conduction block 1.71％,intraventricular conductionblock 4.60％,arrhytmias 10.66％ and other abnormalities 13.04％.The research showed thatthere were various changes in the coded pilots,although no abnormal alteration of the cardio-vascular system was discovered by physical examination,the ECG exercise stress test and otherrelevant clinical tests.This suggests that most of ECG abnormalities in clinically normal pilotsare normal physiological and functional variations.
基金Supported by Key Project of Medical Service Scientific Research of Navy Medical Center,No.20M2302.
文摘BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of specific pulmonary infections in naval pilots.CASE SUMMARY We analyzed the medical waiver and clinical data of four pilots with specific pulmonary infections,who had accepted treatment at the Naval Medical Center of Chinese People’s Liberation Army between January 2020 and November 2021,including three cases of tuberculosis and one of cryptococcal pneumonia.All cases underwent a series of comprehensive treatment courses.Three cases successfully obtained medical waiver for flight after being cured,while one was grounded after reaching the maximum flight life after being cured.CONCLUSION Chest computed tomography scanning should be used instead of chest radiography in pilots’physical examination.Most pilots with specific pulmonary infection can be cured and return to flight.
文摘This study aims to explore dimensions of quality of work life (QWL) of pilots by using an exploratory factor analysis (EFA). The sample was 400 pilots who are currently working for an airline based in Thailand. The items using in this study were generated using input from three sources. First, using input from commercial pilots who had a minimum of total 5,000 flying hour and currently working for either premium or low cost airlines in Thailand. Second, translated quality of work life items from a published research on Quality of Work Life of Personnel at Dhurakij Pundit University by Chatthai (2016). After the content analysis, the left items for the EFA analysis were 30 items. The Kaiser-Meyer-Olkin (KMO) demonstrated at 0.93. The exploratory factor analysis was to examine the loading patterns of QWL items. A principal component and orthogonal rotation (Verimax method) were chosen. It showed there were five structural factor patterns. The five factors were labored as “Human Resource Management”;“Social Relation”;“Safe Working Environment”;“Work-Life Balance”;and “Fairness and Respect”. Discussion and future research are also discussed.
文摘In wireless orthogonal frequency division multiplexing (OFDM) systems, the time-varying channel is often estimated by algorithms based on pilot symbols. Such an estimator, however, requires statistical prior knowledge that is not easily obtained. Therefore, the pilot tones have to be close enough to fulfill the sampling theorem. In this case the statistical knowledge of the channel is not required to reconstruct correctly the channel impulse response (CIR). This paper explores the optimal placement and number of pilot symbols, we investigate optimal training sequences in OFDM systems and we analyze the number of pilot symbols required to fulfill the sampling theorem. Using a general model for a multipath slowly fading channel, the approach is based on the LS as a criterion of channel estimation while the channel interpolation is done using the piecewise-constant interpolation compromising between complexity and performance. Simulation results demonstrate the good performance of our approach.
文摘With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular line-of-sight.At the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance command.The proposed system’s stability is proven based on the Lyapunov stability criterion.The simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance laws.Furthermore,ISMGL has a more accurate impact angle and fast convergence speed.
文摘Background: Cervical Intraepithelial neoplasia treatments have become essential interventions to manage cervical lesions. Majority of the recipients of these treatments are women within the reproductive age group, who according to literature may be at risk of adverse pregnancy outcomes. This pilot study is part of a study investigating adverse pregnancy outcomes among women who received Cryotherapy, Thermal ablation and Loop Electrosurgical Excision Procedure compared to the untreated women in Zambia. Materials and Methods: This descriptive study analyzed records of 886 (n = 443 treated and n = 443 untreated) women aged 15 - 49 years. The women were either screened with Visual Inspection with Acetic Acid or treated for Cervical Intraepithelial neoplasia at the Adult Infectious Disease Centre between January 2010 and December 2020. Women meeting the criteria were identified using the Visual Inspection with Acetic Acid screening records and telephone interviews to obtain the adverse pregnancy outcome experienced. Data were analysed using STATA version 16 to determine the prevalence and obtain frequency distribution of outcomes of interest. Univariate and multivariable binary logistic regression estimated odds of adverse pregnancy outcomes across the three treatments. Results: The respondents were aged 15 to 49 years. Adverse pregnancy outcomes were observed to be more prevalent in the treatment group (18.5%) compared to the untreated group (5.4%). Normal pregnancy outcomes were lower in the treated (46.3%;n = 443) than the untreated (53.7%;n = 443). The treated group accounted for the majority of abortions (85.2%), prolonged labour (85.7%) and low birth weight (80%), whereas, the untreated accounted for the majority of still births (72.7%). Women treated with cryotherapy (aOR = 2.43, 95% CI = 1.32 - 4.49, p = 0.004), thermal ablation (aOR = 6.37, 95% CI = 0.99 - 41.2, p = 0.052) and Loop Electrosurgical Excision Procedure (aOR = 9.67, 95% CI = 2.17 - 43.1, p = 0.003) had two-, six- and ten-times higher odds of adverse pregnancy outcomes respectively, relative to women who required no treatment. Conclusion: Adverse pregnancy outcomes are prevalent among women who have received treatment in Zambia. The findings indicate that treating Cervical Intraepithelial Neoplasia has been linked to higher chances of experiencing abortion, delivering low birth weight babies and enduring prolonged labor that may result in a caesarean section delivery. Cervical neoplasia treatments, particularly Loop Electrosurgical Excision Procedure, are associated with significantly increased odds of adverse pregnancy outcomes. It is essential to include information about prior Cervical Intraepithelial neoplasia treatment outcomes in obstetric care.
文摘On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according
文摘This study explored the use of multi-physiological signals and simultaneously recorded high-density electroencephalography(EEG),electrocardiogram(ECG),and eye movements to better understand pilots’cognitive behaviour during flight simulator manoeuvres.Multimodal physiological signals were collected from 12 experienced pilots with international aviation qualifications under the wide-angle and impressive vision simulation.The data collection spanned two flight strike missions,each with three mission intensities,resulting in a data set of EEG,ECG,and eye movement signals from six subtasks.The multimodal data were analysed using signal processing methods.The results indicated that,when the flight missions were performed,the pilots’physiological characteristics exhibited rhythmic changes in the power spectrum ofθwaves in the EEG,r-MSSD in the ECG,and average gaze duration.Furthermore,the pilots’physiological signals were more sensitive during the target mission than during the empty target mission.The results also showed correlations between different physiological characteristics.We showed that specific multimodal features are useful for advancing neuroscience research into pilots’cognitive behaviour and processes related to brain activity,psychological rhythms,and eye movement.
文摘裂隙介质渗透结构表现为高度的非均质性与各项异性。为了科学有效地预测某核工程场地裂隙地下水的流动规律,揭示裂隙岩体地下水的渗流特性,笔者等采用Pilot Point调参方法与null space Monte Carlo方法(NSMC),开展了裂隙岩体渗透结构的不确定性分析研究,构建了符合实际水文地质条件的多个渗流数值模型集合。结果表明:该方法获得的各个实现地下水位模拟结果能够与实际观测数据较好吻合,可反映工程场地裂隙地下水动力特征与流动趋势;各个实现的参数化渗透结构在空间上存在一定的差异性,但整体变化趋势是保持一致的,渗透参数的不确定性表现为在实测数据分布区域相对较低,钻孔空白区域相对较高;该方法可以弥补单一、确定性模拟结果在表征裂隙介质渗透结构方面的局限性,有效地降低模型参数的不确定性与随机性。此方法对进一步提升裂隙岩体渗流模拟精度与预测能力,深化裂隙地下水迁移规律的认识具有重要的意义。
