期刊文献+
共找到7,975篇文章
< 1 2 250 >
每页显示 20 50 100
Theoretical Research and Practical Application of the Rural Cultural Enhancement by Creative Designs Under Rural Vitalization-A Case Study of Shanxi Province
1
作者 BAI Lu 《Journal of Literature and Art Studies》 2024年第2期155-164,共10页
To revive the nation,the rural area must be revitalized.Every regional cultural and creative industry has its own development path and practical mode.From the perspective of rural revitalization,this paper conducts re... To revive the nation,the rural area must be revitalized.Every regional cultural and creative industry has its own development path and practical mode.From the perspective of rural revitalization,this paper conducts research on the development model of cultural and creative design,and analyzes the significance of the integration of creative design with rural regional culture.Based on the current situation of rural cultural and creative development in Shanxi Province,this study proposes to form a brand communication chain through the integration between cultural design and rural culture,and the establishment of cultural and creative brands,furthermore,to establish trending topics through multiple channels.Finally,the important practical significance of cultural and creative design in promoting rural economic development and enhancing rural culture value is discussed in this design strategy,so as to actively help the new journey of rural revitalization. 展开更多
关键词 rural vitalization creative designs rural culture SHANXI
下载PDF
A New Result on Regular Designs under Baseline Parameterization
2
作者 Mengru Qin Yuna Zhao 《Open Journal of Applied Sciences》 2024年第2期441-449,共9页
The study on designs for the baseline parameterization has aroused attention in recent years. This paper focuses on two-level regular designs for the baseline parameterization. A general result on the relationship bet... The study on designs for the baseline parameterization has aroused attention in recent years. This paper focuses on two-level regular designs for the baseline parameterization. A general result on the relationship between K-aberration and word length pattern is developed. 展开更多
关键词 Baseline Parameterization K-Aberration Regular Design Word Length Pattern
下载PDF
Application of Blank Symbols in Japanese Architecture and Indoor Designs
3
作者 Zhang Zhanzhi Wu Pengjun Zheng Shaojiang 《Contemporary Social Sciences》 2023年第3期145-155,共11页
A symbol is an expression of meaning,while blank symbols express special meanings.By focusing on the application of blank symbols in Japanese architecture and indoor designs,we analyzed the aesthetic principles in Jap... A symbol is an expression of meaning,while blank symbols express special meanings.By focusing on the application of blank symbols in Japanese architecture and indoor designs,we analyzed the aesthetic principles in Japanese architecture and indoor designs from the perspective of semiotics,such as“Kongji,”“Emptiness,”and“Dying out,”and their minimalist and pure design concepts.Traditional Chinese culture was also further explored,especially the profound influence of the“Chan sect”and the philosophy of“unity of heaven and mankind”on Japanese architecture and designs.This study aims to facilitate the coexistence and mutual appreciation of Chinese and Japanese architectural designs. 展开更多
关键词 Blank symbols Japanese culture architectural designs indoor designs traditional Chinese aesthetics
下载PDF
The action mechanisms and structures designs of F-containing functional materials for high performance oxygen electrocatalysis
4
作者 Gang Wang Shuwei Jia +7 位作者 Hongjing Gao Yewen Shui Jie Fan Yixia Zhao Lei Li Weimin Kang Nanping Deng Bowen Cheng 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期377-397,I0010,共22页
Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a cent... Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts. 展开更多
关键词 Fluorine-containing functional materials Action mechanisms and structure designs Density functional theory Oxygen evolution reaction Oxygen reduction reaction
下载PDF
Artificial intelligence-assisted chiral nanophotonic designs
5
作者 Xuanru Zhang Tie Jun Cui 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2023年第10期2-4,共3页
Chiral nanostructures can enhance the weak inherent chiral effects of biomolecules and highlight the important roles in chiral detection.However,the design of the chiral nanostructures is challenged by extensive theor... Chiral nanostructures can enhance the weak inherent chiral effects of biomolecules and highlight the important roles in chiral detection.However,the design of the chiral nanostructures is challenged by extensive theoretical simulations and explorative experiments.Recently,Zheyu Fang’s group proposed a chiral nanostructure design method based on reinforcement learning,which can find out metallic chiral nanostructures with a sharp peak in circular dichroism spectra and enhance the chiral detection signals.This work envisions the powerful roles of artificial intelligence in nanophotonic designs. 展开更多
关键词 CHIRAL designs CIRCULAR
下载PDF
Inspiration and Innovative Approach in Creating Textile Designs and Prints from Sekondi-Takoradi’s Masquerade Costume Designs
6
作者 Kweku Safo-Ankama Joshua Anim Sumaila Mohammed Sumaila 《Journal of Textile Science and Technology》 2023年第1期52-68,共17页
Masquerade culture is an essential part of Sekondi-Takoradi cultural embodiment. The masquerade festival titled Ankos displays interesting costumes that have artistic elements of potent colour display and performances... Masquerade culture is an essential part of Sekondi-Takoradi cultural embodiment. The masquerade festival titled Ankos displays interesting costumes that have artistic elements of potent colour display and performances. The masquerade costumes manifest intricate fabric decoration techniques for example pleating, folding, gathering, smocking, hand and machine stitching and the use of varied colour schemes. These decorative techniques make costume production laborious, tedious and downtime constraints. In contributing to the innovative approaches to creating textile designs and prints, the study explored the inspirational possibilities of surface designs of the masquerade costume for textile designs and prints. The art-based research design and direct observation as research instrumentation were employed in the artistic creation for the study. Adobe Photoshop was used in the simulation design processes. The study revealed that the simulation design processes produced an innovative imitated visual appearance of the masquerade costume and production processes from a machine-stitched work to a hand-printed fabric. It is recommended that costume makers adopt the contemporary possibility of using hand screen to print hitherto the traditional laborious and tedious process of producing masquerade costumes. 展开更多
关键词 Masquerade Costumes Textile designs and Prints ADAPTATION INSPIRATION Sekondi-Takoradi
下载PDF
Unconventional Designs for Functional Sodium-Sulfur Batteries
7
作者 Jiangfeng Ni Yichen Liu Sheng Zhu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第4期405-415,共11页
Sodium-sulfur(Na–S)batteries that utilize earth-abundant materials of Na and S have been one of the hottest topics in battery research.The low cost and high energy density make them promising candidates for next-gene... Sodium-sulfur(Na–S)batteries that utilize earth-abundant materials of Na and S have been one of the hottest topics in battery research.The low cost and high energy density make them promising candidates for next-generation storage technologies as required in the grid and renewable energy.In recent years,extensive efforts have been devoted to the diversity and functionalities of Na–S batteries,aiming to extend their potential applications across multiple temporal and spatial dimensions.Here,we summarize the unconventional designs for the functionalities of Na–S batteries such as flexible batteries,solid-state cells,flame resistance,and operation at extreme temperatures.By highlighting these design strategies that help to realize the functionalities,we hope this review offers a pathway to foster the bright future of Na–S batteries in diverse applications. 展开更多
关键词 flexibility multiple functionalities sodium-sulfur batteries unconventional design
下载PDF
Construction of Split-Plot Designs with General Minimum Lower Order Confounding
8
作者 Kexin Li Beichen Han Zhenzhen Niu 《Open Journal of Applied Sciences》 CAS 2023年第3期261-274,共14页
Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attracti... Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attractive design criterion for selecting fractional factorial split-plot design. In this paper, we are interested in the theoretical construction methods of the optimal fractional factorial split-plot designs under the general minimum lower order confounding criterion. We present the theoretical construction methods of optimal fractional factorial split-plot designs under general minimum lower order confounding criterion under several conditions. 展开更多
关键词 Fractional Factorial Design General Minimum Lower Order Confounding Criterion Split-Plot Design
下载PDF
Joint Transceiver Designs for Full-Duplex MIMO SWIPT Systems Based on MSE Criterion 被引量:4
9
作者 Zhigang Wen Xiaoqing Liu +2 位作者 Yancun Chen Rui Wang Zhimin Xie 《China Communications》 SCIE CSCD 2016年第10期79-85,共7页
For the simultaneous wireless information and power transfer(SWIPT), the full-duplex MIMO system can achieve simultaneous transmission of information and energy more efficiently than the half-duplex. Based on the mean... For the simultaneous wireless information and power transfer(SWIPT), the full-duplex MIMO system can achieve simultaneous transmission of information and energy more efficiently than the half-duplex. Based on the mean-square-error(MSE) criterion, the optimization problem of joint transceiver design with transmitting power constraint and energy harvesting constraint is formulated. Next, by semidefinite relaxation(SDR) and randomization method, the SDRbased scheme is proposed. In order to reduce the complexity, the closed-form scheme is presented with some simplified measures. Robust beamforming is then studied considering the practical condition. The simulation results such as MSE versus signal-noise-ratio(SNR), MSE versus the iteration number, well prove the performance of the proposed schemes for the system model. 展开更多
关键词 full-duplex mean-square-error(MSE) joint transceiver designs power splitting ROBUST
下载PDF
Machine-Learning-Assisted Optimization and Its Application to Antenna Designs: Opportunities and Challenges 被引量:2
10
作者 Qi Wu Yi Cao +1 位作者 Haiming Wang Wei Hong 《China Communications》 SCIE CSCD 2020年第4期152-164,共13页
With the rapid development of modern wireless communications and radar, antennas and arrays are becoming more complex, therein having, e.g., more degrees of design freedom, integration and fabrication constraints and ... With the rapid development of modern wireless communications and radar, antennas and arrays are becoming more complex, therein having, e.g., more degrees of design freedom, integration and fabrication constraints and design objectives. While fullwave electromagnetic simulation can be very accurate and therefore essential to the design process, it is also very time consuming, which leads to many challenges for antenna design, optimization and sensitivity analysis(SA). Recently, machine-learning-assisted optimization(MLAO) has been widely introduced to accelerate the design process of antennas and arrays. Machine learning(ML) methods, including Gaussian process regression, support vector machine(SVM) and artificial neural networks(ANNs), have been applied to build surrogate models of antennas to achieve fast response prediction. With the help of these ML methods, various MLAO algorithms have been proposed for different applications. A comprehensive survey of recent advances in ML methods for antenna modeling is first presented. Then, algorithms for ML-assisted antenna design, including optimization and SA, are reviewed. Finally, some challenges facing future MLAO for antenna design are discussed. 展开更多
关键词 ANTENNA designs MACHINE learning OPTIMIZATION sensitivity analysis surrogate models
下载PDF
Factorial Designs Application to Study Enhanced Bioremediation of Soil Artificially Contaminated with Weathered Bonny Light Crude Oil through Biostimulation and Bioaugmentation Strategy 被引量:2
11
作者 Samuel E. Agarry Oladipupo O. Ogunleye 《Journal of Environmental Protection》 2012年第8期748-759,共12页
The objective of this study was designed to evaluate the effects of biostimulation and bioaugmentation amendment agents (NPK fertilizer, Tween 80 and mixed culture) on the bioremediation of tropical soil samples artif... The objective of this study was designed to evaluate the effects of biostimulation and bioaugmentation amendment agents (NPK fertilizer, Tween 80 and mixed culture) on the bioremediation of tropical soil samples artificially contaminated with Weathered Bonny Light Crude Oil (WBLCO). Response Surface Methodology (RSM) with Box Behnken Design (BBD) was used with three levels and three factors of NPK fertilizer (2 - 6 g), Tween 80 (5 - 15 mg/l) and mixed culture (0.5 - 1.5 g/l) as independent variables and WBLCO removal as dependent variable (response) in a six weeks remediation period. The results showed that the rate of WBLCO removal generally increased with increase in the amount of NPK fertilizer, Tween 80 and mixed culture (biomass), respectively. A statistically significant (P < 0.0001) second-order quadratic regression model for WBLCO removal (using design-expert statistical program (v. 6.0.8)) with a coefficient of determination, R (=0.9996) was obtained. Numerical optimization technique based on desirability function was carried out to optimize the bioremediation process. The optimum values for biostimulation and bioaugmentation amendment agents to achieve a predicted maximum WBLCO removal of 84.88 percent were found to be: NPK fertilizer, 4.25 g;Tween 80, 10.22 mg/l and mixed culture, 0.46 g/l. At this optimum point, the observed WBLCO removal was found to be 83.79 percent. The statistical analyses and the closeness of the experimental results and model predictions show the reliability of the regression model and thus, biostimulation and bioaugmentation of indigenous microbial density and activity can reduce remediation period of petroleum hydrocarbon contaminated environment and subsequently the cost of remediation. 展开更多
关键词 BIOREMEDIATION Box-Behnken designs CRUDE Oil SECOND-ORDER Quadratic Regression Model
下载PDF
A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs 被引量:1
12
作者 B. Re. Victorbabu K. Rajyalakshmi 《Open Journal of Statistics》 2012年第1期39-47,共9页
The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs... The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi. The above paper is a copy of Dr. Rabindra Nath Das’s former article, entitled '“Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we solemnly withdrawn?the paper from the journal OJS. This paper published in OJS Vol.2 No.1, 39-47, 2012, has been retracted. 展开更多
关键词 Response Surface designs Rotatability Second Order Rotatable designs (SORD) ROBUST SORD ROBUSTNESS BALANCED INCOMPLETE Block designs
下载PDF
Comment on "Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification" 被引量:1
13
作者 Neelima Aron Sagnik Sen Sudarshan Khokhar 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2017年第8期1334-1336,共3页
Citation:Aron N,Sen S,Khokhar S.Comment on'Comparison of45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification'.Int J Ophthalmol 2017;10(8):1334-1336Dear Editor... Citation:Aron N,Sen S,Khokhar S.Comment on'Comparison of45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification'.Int J Ophthalmol 2017;10(8):1334-1336Dear Editor,We read with interest the article'Comparison of45-degree Kelman and 45-degree balanced phaco 展开更多
关键词 Vision Comment on Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification
原文传递
Half Rate Quasi Cyclic Low Density Parity Check Codes Based on Combinatorial Designs 被引量:2
14
作者 Sina Vafi Narges Rezvani Majid 《Journal of Computer and Communications》 2016年第12期39-49,共12页
This paper presents new half rate Quasi Cyclic Low Density Parity Check (QC- LDPC) codes formed on the basis of combinatorial designs. In these codes, circulant matrices of the parity check matrix are formed on the ba... This paper presents new half rate Quasi Cyclic Low Density Parity Check (QC- LDPC) codes formed on the basis of combinatorial designs. In these codes, circulant matrices of the parity check matrix are formed on the basis of subsets in which the difference between any two elements of a subset is unique with all differences obtained from the same or different subsets. This structure of circulant matrices guarantees non-existence of cycle-4 in the Tanner graph of QC-LDPC codes. First, an irregular code with girth 6 constituted by two rows of circulant matrices is proposed. Then, more criteria will be considered on the structure of subsets with the mentioned feature aiming to represent a new scheme of regular QC-LPDC codes with girth at least 8. From simulations, it is confirmed that codes have similar to or better performance than other well-known half rate codes, while require lower complexity in their design. 展开更多
关键词 Quasi-Cyclic LDPC Codes Combinatorial designs Circulant Matrix
下载PDF
Recent developments in optimal experimental designs for functional magnetic resonance imaging
15
作者 Ming-Hung Kao M'hamed Temkit Weng Kee Wong 《World Journal of Radiology》 CAS 2014年第7期437-445,共9页
Functional magnetic resonance imaging(fMRI)is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli.For neuroimaging studies utilizing this pioneering technology,there... Functional magnetic resonance imaging(fMRI)is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli.For neuroimaging studies utilizing this pioneering technology,there is a great demand of high-quality experimental designs that help to collect informative data to make precise and valid inference about brain functions.This paper provides a survey on recent developments in experimental designs for fMRI studies.We briefly introduce some analytical and computational tools for obtaining good designs based on a specified design selection criterion.Research results about some commonly considered designs such as blocked designs,and m-sequences are also discussed.Moreover,we present a recently proposed new type of fMRI designs that can be constructed using a certain type of Hadamard matrices.Under certain assumptions,these designs can be shown to be statistically optimal.Some future research directions in design of fMRI experiments are also discussed. 展开更多
关键词 A-OPTIMALITY Blocked designs Design EFFICIENCIES D-OPTIMALITY Genetic algorithms HADAMARD sequences M-SEQUENCES
下载PDF
In-plane micro-sized energy storage devices:From device fabrication to integration and intelligent designs
16
作者 Songshan Bi Hongmei Cao +2 位作者 Rui Wang Fang Wan Zhiqiang Niu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第12期25-39,I0002,共16页
The rapid development of micro-electronics raises the demand of their power sources to be simplified,miniaturized and highly integratable with other electronics on a chip.In-plane Micro-sized energy storage devices(ME... The rapid development of micro-electronics raises the demand of their power sources to be simplified,miniaturized and highly integratable with other electronics on a chip.In-plane Micro-sized energy storage devices(MESDs),which are composed of interdigitated electrodes on a single chip,have aroused particular attentions since they could be easily integrated with other miniaturized electronics,reducing the complexity of overall chip design via removing complex interconnections with bulky power sources.This review highlights the achievements in the device fabrication of in-plane MESDs,as well as their integration and intelligent designs.We also discussed the current challenges and future perspectives for the development of in-plane MESDs. 展开更多
关键词 Micro-sized energy storage devices Micro-batteries Micro-supercapacitors INTEGRATION Intelligent designs
下载PDF
On Network Designs with Coding Error Detection and Correction Application
17
作者 Mahmoud Higazy Taher A.Nofal 《Computers, Materials & Continua》 SCIE EI 2021年第6期3401-3418,共18页
The detection of error and its correction is an important area of mathematics that is vastly constructed in all communication systems.Furthermore,combinatorial design theory has several applications like detecting or ... The detection of error and its correction is an important area of mathematics that is vastly constructed in all communication systems.Furthermore,combinatorial design theory has several applications like detecting or correcting errors in communication systems.Network(graph)designs(GDs)are introduced as a generalization of the symmetric balanced incomplete block designs(BIBDs)that are utilized directly in the above mentioned application.The networks(graphs)have been represented by vectors whose entries are the labels of the vertices related to the lengths of edges linked to it.Here,a general method is proposed and applied to construct new networks designs.This method of networks representation has simplified the method of constructing the network designs.In this paper,a novel representation of networks is introduced and used as a technique of constructing the group generated network designs of the complete bipartite networks and certain circulants.A technique of constructing the group generated network designs of the circulants is given with group generated graph designs(GDs)of certain circulants.In addition,the GDs are transformed into an incidence matrices,the rows and the columns of these matrices can be both viewed as a binary nonlinear code.A novel coding error detection and correction application is proposed and examined. 展开更多
关键词 Network decomposition network designs network edge covering circulant graphs
下载PDF
Some Remarks on the Non-Abelian Fourier Transform in Crossover Designs in Clinical Trials
18
作者 Peter Zizler 《Applied Mathematics》 2014年第6期917-927,共11页
Let G be a non-abelian group and let l2(G) be a finite dimensional Hilbert space of all complex valued functions for which the elements of G form the (standard) orthonormal basis. In our paper we prove results concern... Let G be a non-abelian group and let l2(G) be a finite dimensional Hilbert space of all complex valued functions for which the elements of G form the (standard) orthonormal basis. In our paper we prove results concerning G-decorrelated decompositions of functions in l2(G). These G-decorrelated decompositions are obtained using the G-convolution either by the irreducible characters of the group G or by an orthogonal projection onto the matrix entries of the irreducible representations of the group G. Applications of these G-decorrelated decompositions are given to crossover designs in clinical trials, in particular the William’s 6×3?design with 3 treatments. In our example, the underlying group is the symmetric group S3. 展开更多
关键词 Non-Abelian Fourier Transform Group Algebra IRREDUCIBLE Representation IRREDUCIBLE Character G-Circulant Matrix G-Decorrelated Decomposition CROSSOVER designs in Clinical Trials
下载PDF
A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs
19
作者 B. Re. Victorbabu K. Rajyalakshmi 《Open Journal of Statistics》 2012年第3期319-327,共9页
The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. ... The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi.The paper is a copy of Dr. Rabindra Nath Das’s former article, entitled “Slope rotatability with correlated errors (Vol. 54, pp. 57-70, 2003)” and “Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in OJSVol.2 No.3, 319-327, 2012, has been removed from this site. 展开更多
关键词 Response Surface designs SLOPE Rotatability CORRELATED ERRORS ROBUSTNESS Second Order SLOPE Rotatable designs (SOSRD)
下载PDF
Comparative Analysis of Group Sequential Designs Tests for Randomized Controlled Clinical Trials: A Model Study on Two-Sided Tests for Comparing Two Treatments
20
作者 Mehmet Ali Sungur Emine Arzu Kanik 《Open Journal of Statistics》 2012年第1期60-72,共13页
Clinical trials are usually long term studies and it seems impossible to reach all required subjects at the same time. Performing interim analyses and monitoring results may provide early termination of trial after ob... Clinical trials are usually long term studies and it seems impossible to reach all required subjects at the same time. Performing interim analyses and monitoring results may provide early termination of trial after obtaining significant results. The aim of this study is comparing group sequential tests in respect to advantage of sample size reduction and early termination. In this study, 4 test types used in group sequential designs were compared with fixed sample size design test and each other. Comparisons were done according to two-sided tests for comparing two treatments. In this sense, 1080 models were performed. In models, 2 different Type I errors, 2 different powers, 5 different analysis groups, 6 different effect sizes and 9 different variances selections were considered. All test types increased the maximum sample size in different manner, compared with fixed sample size design. Each test had different critical values to reject H0 hypothesis, at the same type I error rate and number of analyses conditions. Selection of test type used in group sequential designs depends on a few characteristics, as reducing sample size, early termination and detecting minimal effect size. Test performance is highly related with selected Type I error rate, power and number of analyses. In addition to these statistical characteristics, researchers should decide test type with respect to other trial conditions as the issue of trial, reaching subjects easy or not and importance of early termination. 展开更多
关键词 GROUP SEQUENTIAL designs GROUP SEQUENTIAL Test Types Interim Analysis Monitoring
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部