A Probabilistic Analysis for Periodicity of Real-time Tasks

Raimarius Delgado,Byoung Wook Choi 한국인터넷방송통신학회 2021 International Journal of Internet, Broadcasting an Vol.13 No.1

This paper proposes a probabilistic method in analyzing timing measurements to determine the periodicity of real-time tasks. The proposed method fills a gap in existing techniques, which either concentrate on the estimation of worst-case execution times, or do not consider the stochastic behavior of the real-time scheduler. Our method is based on the Z-test statistical analysis which calculates the probability of the measured period to fall within a user-defined standard deviation limit. The distribution of the measured period should satisfy two conditions: its center (statistical mean) should be equal to the scheduled period of the real-time task, and that it should be symmetrical with most of the samples focused on the center. To ensure that these requirements are met, a data adjustment process, which omits any outliers in the expense of accuracy, is presented. Then, the Z-score of the distribution according to the user-defined deviation limit provides a probability which determines the periodicity of the real-time task. Experiments are conducted to analyze the timing measurements of real-time tasks based on real-time Linux extensions of Xenomai and RT-Preempt. The results indicate that the proposed method is able to provide easier interpretation of the periodicity of real-time tasks which are valuable especially in comparing the performance of various real-time systems.

Overview of Real-Time Java Computing

Yu Sun,Wei Zhang 한국정보과학회 2013 Journal of Computing Science and Engineering Vol.7 No.2

This paper presents a complete survey of recent techniques that are applied in the field of real-time Java computing. It focuses on the issues that are especially important for hard real-time applications, which include time predictable garbage collection, worst-case execution time analysis of Java programs, real-time Java threads scheduling and compiler techniques designed for real-time purpose. It also evaluates experimental frameworks that can be used for researching real-time Java. This overview is expected to help researchers understand the state-of-the-art and advance the research in real-time Java computing.

Real-time Estimation and Analysis of Time-based Accessibility and Usability for Ubiquitous Mobile-Web Services

( Yung Bok Kim ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.5

Ubiquitous web services have been expanding in various business areas with the evolution of wireless Internet technologies, accessible and usable with a variety of mobile Internet devices such as smart phones. Ubiquitous mobile-web information services can be evaluated for accessibility and usability with the mobile Internet devices interacting with mobile-web information servers. In human mobile-web activity, a web server could be a unified center for mobile-web interaction services as well as for real-time estimation and analysis of mobile-web interaction sessions. We present a real-time estimation and analysis scheme for time-based accessibility and usability in ubiquitous mobile-web services. With real-time estimation/analysis of sessions in a mobile-web server, we estimated the time-based accessibility and usability for comparison between different web services as well as for applications in mobile cloud computing services. We present empirical results based on the implementation of the real-time estimation/analysis scheme.

Detection of α-thalassemia-1 Southeast Asian and Thai Type Deletions and β-thalassemia 3.5-kb Deletion by Single-tube Multiplex Real-time PCR with SYBR Green1 and High-resolution Melting Analysis

Sakorn Pornprasert,Thanatcha Wiengkum,Sarinee Srithep,Isarapong Chainoi,Panthong Singboottra,Sanchai Wongwiwatthananukit 대한진단검사의학회 2011 Annals of Laboratory Medicine Vol.31 No.3

Background: Prevention and control of thalassemia requires simple, rapid, and accurate screening tests for carrier couples who are at risk of conceiving fetuses with severe thalassemia. Methods: Single-tube multiplex real-time PCR with SYBR Green1 and high-resolution melting (HRM) analysis were used for the identification of α-thalassemia-1 Southeast Asian (SEA) and Thai type deletions and β-thalassemia 3.5-kb gene deletion. The results were compared with those obtained using conventional gap-PCR. DNA samples were derived from 28 normal individuals, 11 individuals with α-thalassemia-1 SEA type deletion, 2 with α-thalassemia-1 Thai type deletion, and 2 with heterozygous β-thalassemia 3.5-kb gene deletion. Results: HRM analysis indicated that the amplified fragments from α-thalassemia-1 SEA type deletion, α-thalassemia-1 Thai type deletion, β-thalassemia 3.5-kb gene deletion, and the wild-type β-globin gene had specific peak heights at mean melting temperature (T_m) values of 86.89˚C, 85.66˚C, 77.24˚C, and 74.92˚C, respectively. The results obtained using single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis showed 100% consistency with those obtained using conventional gap-PCR. Conclusions: Single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis is a potential alternative for routine clinical screening of the common types of α- and β-thalassemia large gene deletions, since it is simple, cost-effective, and highly accurate. Background: Prevention and control of thalassemia requires simple, rapid, and accurate screening tests for carrier couples who are at risk of conceiving fetuses with severe thalassemia. Methods: Single-tube multiplex real-time PCR with SYBR Green1 and high-resolution melting (HRM) analysis were used for the identification of α-thalassemia-1 Southeast Asian (SEA) and Thai type deletions and β-thalassemia 3.5-kb gene deletion. The results were compared with those obtained using conventional gap-PCR. DNA samples were derived from 28 normal individuals, 11 individuals with α-thalassemia-1 SEA type deletion, 2 with α-thalassemia-1 Thai type deletion, and 2 with heterozygous β-thalassemia 3.5-kb gene deletion. Results: HRM analysis indicated that the amplified fragments from α-thalassemia-1 SEA type deletion, α-thalassemia-1 Thai type deletion, β-thalassemia 3.5-kb gene deletion, and the wild-type β-globin gene had specific peak heights at mean melting temperature (T_m) values of 86.89˚C, 85.66˚C, 77.24˚C, and 74.92˚C, respectively. The results obtained using single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis showed 100% consistency with those obtained using conventional gap-PCR. Conclusions: Single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis is a potential alternative for routine clinical screening of the common types of α- and β-thalassemia large gene deletions, since it is simple, cost-effective, and highly accurate.

Evaluation of key-strokes on the basketball game analysis software

최형준(Hyong Jun Choi) 한국체육측정평가학회 2013 한국체육측정평가학회지 Vol.15 No.3

경기분석 소프트웨어의 발달이 스포츠경기력을 향상시키는데 도움을 주듯이, 소프트웨어의 평가는 스포츠와 인간 공학 분야에 관계가 있다. 스포츠경기분석 소프트웨어를 실시간 분석환경에서 사용하기 위해서는 자료수집, 자료 분석의 시간적, 조작적 제한을 고려해야 하며, 실시간 분석환경에서의 경기분석 소프트웨어 사용은 앞선 제한점을 최근의 컴퓨터기술과 체계화된 분석 과정 속에서 축소시킬 수 있다(Choi, 2008; Choi, Hughes, & O``Donoghue, 2007). 따라서 본 연구의 목적은 2005-2006, 2006-2007년도 영국 여자 농구대회(Div 2)에서 사용된 농구 경기분석 소프트웨어의 키 스트로크를 비교하여 분석 과정 속에서 소프트웨어 사용의 변화치를 측정하고, 이를 논의하는 데 있다. 경기 기록은 농구 경기분석 프로그램인 CyberSport for Basketball™ 4.0을 사용하였을 때 기록된 자료를 의미하며, 소프트웨어의 키 스트로크를 측정하기 위해 Blacksun사의 Mousotron™ 4.7을 사용하였다. 수집된 자료는 Mann-Whitney U 검정, 독립 T검정 그리고 빈도분석을 통해 분석되었다. 본 연구를 통해 얻은 결과는 첫째, 두 시즌 간의 분석 시간(2005 - 2006 시즌 - 85.3±4.7 분, 2006 - 2007 시즌 - 283.6 ± 4.6 분) 사이에는 유의한 차이가 없다. 둘째, 두 시즌 간의 총 스트로크 수(2005 - 2006 시즌 - 1198.3±143.3 회, 2006 - 2007 시즌 - 1316.0±164.9 회, p<.05)와 분석시간(분)당 스트로크 수(2005 - 2006 시즌 - 14.1±1.7/min, 2006 - 2007 시즌 - 15.8±1.8/min, p<.05)에는 통계적으로 유의한 차이를 보였다. 결과적으로 스트로크 횟수가 증가하면 분석시간이 증가되는 점에 있어서 통계적으로 유의한 차이를 나타내지 못 했지만, 경기가 진행되는 과정에서의 분석 강도에 의하여 스트로크 횟수가 증가되어도 분석시간은 감소하는 것으로 풀이된다. 따라서 경기분석 소프트웨어를 활용하여 기록자가 경기내용과 경기기록을 실시간으로 수집할 경우 분석 강도와 분석시간 등을 고려해야만 하며, 스트로크 수를 최대한 감소시킬 수 있는 도구를 선택해야 할 것으로 사료된다. 이 연구의 자료를 토대로 향후 연구에서는 소프트웨어의 평가를 스포츠경기흐름의 강도를 측정할 수 있는 지표개발이 이루어진다면 실시간 경기분석을 위한 소프트웨어 개발에 도움을 줄 수 있을 것이다. As the development of match analysis software has enhanced performance in sports, the evaluation of the applications is currently relevant in the field of sport and ergonomics. In order to utilize those applications or systems in real-time situations, however, limits of data collection, data analysis, time and validity of the data must be addressed in match analysis applications. Modern technologies, on the other hand, tend to overcome the limitations of match analysis applications by the construction or internal procedure (Choi, 2008; Choi, Hughes, & O` Donoghue, 2007). The main aim of this study, therefore, is to compare the key strokes of basketball match analysis software between the England Women Basketball DIV 2 2005-2006 and 2006-2007. The game data were collected in real-time by Cyber Sport for Basketball ™ 4.0 and then determined by Mann-Whitney U test, independent T-test and descriptive statistics. As results, there were no significant differences found on analysis time (85.3±4.7 minutes in 2005-2006, 83.6±4.6 minutes in 2006-2007), but there were significant differences on the total strokes by key presses/mouse clicks ( 1198.3±143.3 in 2005-2006, 1316.0±164.9 in 2006-2007, p<0.05) and the strokes per analysis minute ( 14.1±1.7/min in 2005-2006, 15.8±1.8/min in 2006-2007, p<0.05) between the seasons. Consequently, the ascend numbers of strokes and descend minutes of analysis time have found in the comparison despite of no difference between analysis time statistically that the intensity of analysis depended on game process would have caused the results of the study. Therefore, the application on the match analysis software has to be concerned for all operators who collate performance data or match data using such software. For further research, the development of game intensity index is required in order to evaluate the software evenly.

고정반복법에 의한 암시적 HHT 시간적분법을 이용한 철근콘크리트 골조구조물의 실시간 하이브리드실험

강대흥,김성일 한국지진공학회 2011 한국지진공학회논문집 Vol.15 No.5

고정반복법에 의한 암시적 HHT 시간적분법을 이용하여 3층 3경간 철근콘크리트 골조구조물을 수치해석모형과 물리적 분구조모형으로 나누어 실시간 하이브리드실험을 실시하였다. 물리적 부분구조모형으로는 1층 내부 비연성기둥 1개소가 선택되었고, 수치해석모형에 일축 방향의 지진하중을 시편이 심한 손상에 의하여 파괴에 이를 때까지 작용시켰다. 비선형 유한요소해석 프로그램인 Mercury가 실시간 하이브리드실험을 위하여 새로이 개발 및 적용되었다. 실험결과는 물리적 부분구조모형의 상부 수평방향 층간변위비를 OpenSees에 의한 수치해석시뮬레이션과 진동대실험의 그것과 비교하였다. 본 실험은 가장 복잡한 실시간 하이브리드실험 중의 하나이고, 하드웨어, 알고리즘 그리고 모형에 대한 기술적인 내용을 본 논문에 자세히 설명하였다. 수치해석모형의 개선, 물리적 부분구조 모형 접선강성행렬의 유한요소해석 프로그램에서의 평가 그리고 하중기반 보-요소의 요소상태결정의 연산시간을 줄이기 위한 소프트웨어의 개선이 이루어진다면 실시간 하이브리드실험과 진동대실험결과의 비교는 권장할 만하다. 그리고 "지진과 같은 동적하중하의 복잡한 구조물의 수치해석시뮬레이션"이라는 목적을 위하여 실시간 하이브리드실험은 동적하중에 대한 실험적 검증을 점진적으로 수치해석모형으로 대체하기 위한 저비용-고효율 실험법으로서의 가치를 충분히 가지고 있다고 할 수 있다. A real-time hybrid test of a 3 story-3 bay reinforced concrete frame which is divided into numerical and physical substructure models under uniaxial earthquake excitation was run using a fixed iteration implicit HHT time integration method. The first story inner non-ductile column was selected as the physical substructure model, and uniaxial earthquake excitation was applied to the numerical model until the specimen failed due to severe damage. A finite-element analysis program, Mercury, was newly developed and optimized for a real-time hybrid test. The drift ratio based on the top horizontal displacement of the physical substructure model was compared with the result of a numerical simulation by OpenSees and the result of a shaking table test. The experiment in this paper is one of the most complex real-time hybrid tests, and the description of the hardware, algorithm and models is presented in detail. If there is an improvement in the numerical model, the evaluation of the tangent stiffness matrix of the physical substructure model in the finite element analysis program and better software to reduce the computational time of the element state determination for the force-based beam-column element, then the comparison with the results of the real-time hybrid test and the shaking table test deserves to make a recommendation. In addition, for the goal of a "Numerical simulation of the complex structures under dynamic loading", the real time hybrid test has enough merit as an alternative to dynamic experiments of large and complex structures.

Real-Time Travel-Time Prediction Method Applying Multiple Traffic Observations

임성한,김영호,이청원 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.7

Various methods have been developed to predict automobile travel time, but they are often unreliable, especially when the travel time varies significantly during the transition between free flow and congested flow. This paper proposes a real-time travel-time prediction method. We apply a macroscopic traffic flow model with predicted boundary conditions and modify the scheme to calculate the traffic states to reflect the latest traffic conditions on a real-time basis. Our method uses traffic data from multiple observation systems, which is a crucial component for real-time application of the macroscopic traffic flow model that has not been previously applied to traffic flow models. The analysis of real traffic data collected from a section of the Korean Kyungbu Expressway shows that the proposed method outperforms other prediction methods, particularly during the transition between free flow and congested flow.

C-DEVS형식론을 이용한 실시간 이산사건 제어시스템의 논리 해석 기법

송해상(HAESANG SONG)김탁곤(Tag-Gon Kim) 한국시뮬레이션학회 2012 한국시뮬레이션학회 논문지 Vol.21 No.4

실시간 시스템의 복잡도가 증가함에 따라 임시방편적 시스템 해석 방법은 시스템 동작 영역 전체를 완전하게 분석하는 데는 한계가 있다. 모델링을 기반으로 한 정형 기법은 그러한 한계점을 극복 할 수 있다. 본 논문은 모델 기반 정형 기법을 이용하여 실시간 시스템의 안전성 및 필연성 등과 같은 논리적 타당성을 이산 사건 모델 수준에서 분석하는 방법을 제안한다. 먼저, 분석 대상 실시간 시스템은 이산사건 수준에서 계층적으로 모듈화하여 모델을 명세하는 수학적 형식론인 DEVS (Discrete Event Systems Specification) 형식론으로 기술된다. 다음으로, 기술된 DEVS 모델은 시간 명세가 포함된 전역 상태 공간을 표현하는 C-DEVS (Communicating DEVS) 형식론으로 표현한 후 C-DEVS 형식론의 해석 알고리즘을 통해 시스템 동작을 분석된다. 제안된 C-DEVS 형식론 및 해석 알고리즘은 주어진 시스템의 동작 특성을 분석하는 과정에서 시스템의 상태 공간을 완전하게 빠짐없이 탐색하는 것을 보장한다. 간단한 건널목 제어 시스템의 안전성 분석 사례 연구를 통하여 제안된 모델 기반 해석 기법의 효율성을 예시 하였다. As complexity of real-time systems is being increased ad hoc approaches to analysis of such systems would have limitations in completeness and coverability for states space search. Formal means using a model-based approach would solve such limitations. This paper proposes a model-based formal method for logical analysis, such as safety and liveness, of real-time systems at a discrete event system level. A discrete event model for real-time systems to be analyzed is specified by DEVS(Discrete Event Systems Specification) formalism, which specifies a discrete event system in hierarchical, modular manner. Analysis of such DEVS models is performed by Communicating DEVS (C-DEVS) formalism of a timed global state transition specification and an associated analysis algorithm. The C-DEVS formalism and an associated analysis algorithm guarantees that all possible states for a given system are visited in an analysis phase. A case study of a safety analysis for a rail road crossing system illustrates the effectiveness of the proposed method of the model-based approach.

The identification of optimal data range for the discrimination between won and lost

한도령,최형준 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.7

성과를 나타내는 지표는 스포츠 성과 향상을 나타내는 기본 요소를 식별하기 위해 개발되었다. 유효한 성과 지표를 식별하려면 성과 분석 시스템 내에서 사용 된 지표가 경기 내에서 성과의 승패를 구별하는 것이 매우 중요하다고 할 수 있다. (Hughes and Bartlett, 2002). 그러나 농구 성과에관한 연구에서는 제안된 성과와 지표는 코치 및 선수의 상황에 따라 실시간 분석 및 피드백이 사용되지 않고 있다는 점이다. 코치 및 선수에 대한 이러한 실시간 지원은 다른 스포츠에 대한 연구에서도 설명되고 있다. (Choi et al., 2004; O'Donoghue, 2001; Palmer et al., 1997). 실시간 피드백 프로세스 내에서 성과와 손실을 구분하는 관련성과 지표를 식별하는 것이 실시간 분석 시스템 개발의 첫 단계가 되어야 한다. 따라서 이 연구는 10 개의 잉글랜드 내셔널 농구리그 경기를 분석하는 동안 수집 된 성과 지표 세트 측면에서 팀의 승패와 패배의 차이점을 조사하였다. 승리와 패배 팀은 전체 경기 데이터 (N=10)와 개별 쿼터 (N=40)를 사용하여 비교되었다. 일련의 Wilcoxon Signed Ranks 테스트를 사용하여 전체 경기와 개별 쿼터 내에서 성과를 낸 사람과 잃는 사람을 구별하는 관련성과 지표를 식별하였다. 테스트 결과 3점 (p<0.05)과 어시스트 (p<0.05)는 경기 내 팀의 승패에서 크게 차이가 있다고 할 수있다. 그러나 2점 슛 (p <0.05), 2점 샷 시도 (P <0.05), 2 점 샷의 백분율 (p <0.05), 3 점 샷 (p <0.05), 수비 리바운드 (p <0.05) ) 및 지원 (p <0.05)은 분기 내 실적의 승패에서 크게 다르게 나타나고 있다. 위와 같은 분석 작업은 성과분석에 따라 코치에게 현재 성과를 설명하는 관련성과 지표를 기반으로 해야 한다. 실시간 분석 및 피드백 시나리오 내에서 가장 최근 분기 내에서 즉각적인 성과를 기반으로 의사 결정을 지원하는 추가 이점이 있다. 결과적으로, 실시간 분석 시스템은 코치의 결정을 뒷받침하기 위해 필요하며 유효성 특성을 갖는 성능 지표를 사용한다. Performance indicators have often investigated and developed in order to identify foundational elements and factors for an enhancement of performance in sports. In order to identify the valid performance indicators it is important that the indicators used within a performance analysis system discriminate between the winning and losing performances within a match (Hughes and Bartlett, 2002). However, the performance indicators proposed in research studies on basketball performance have not been used for real-time analysis and feedback within a coaching context. Such real-time support for the coach and players has been described within research on other sports (Choi et al., 2004; O'Donoghue, 2001; Palmer et al., 1997). Within the process of real-time feedback, the identification of relevant performance indicators that distinguish winning and losing performances should be the first stage of the development of a real-time analysis system. Therefore, this study investigated the differences between winning and losing teams in terms of a set of performance indicators gathered during the analysis of 10 English National Basketball League matches. Winning and losing teams were compared using whole match data (N=10) as well as individual quarters (N=40). A series of Wilcoxon Signed Ranks tests was used to identify the relevant performance indicators that discriminate between winning and losing performers within whole matches and individual quarters. The tests found that 3 point shots made (p<0.05) and Assists (p<0.05) were significantly different between winning and losing teams within matches. However, 2 point shots made (p<0.05), 2 point shots attempted (P<0.05), percentages of 2 point shots scored (p<0.05), 3 point shots made (p<0.05), Defensive Rebounds (p<0.05) and Assists (p<0.05) were significantly different between winning and losing performance within quarters. The analysis task should be based on relevant performance indicators which explain the current performances to performance analysts and coaches. Within a real-time analysis and feedback scenario, this will have the additional benefit of supporting a decision based on immediate performance within the most recent quarter. Consequently, the real-time analysis system would use performance indicators which have the property of construct validity to support the decisions of the coach

FPGA‑based real‑time simulation of LCC‑HVDC systems with C‑NAM method

Ruolan Li,Danyong Li,Yang Gao,Chen Gu,Xiaoyi Sun,Li Fan 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.6

The real-time simulation of a line-commutated converter-high voltage direct current (LCC-HVDC) system based on a field programmable gate array (FPGA) is proposed to meet the increasingly complex dynamic characteristics and real-time simulation requirements of HVDCs. In addition, a real-time simulation platform based on a CPU + FPGA is established forsimulation verification. First, a simulation model of the 12-pulse rectifier of an LCC-HVDC is established using the compact nodal analysis method (C-NAM). When compared with the traditional node analysis method, C-NAM reduces the number of multiplication executions in a single simulation step, and the degree of program serialization is signifi cantly reduced,which greatly improves the real-time simulation speed of a FPGA. Then, this simulation model is programmed in a FPGA, and the optimization algorithm further shortens the simulation step size. Finally, a 12-pulse LCC-HVDC is compared and verified with a 1 μs simulation step on a FPGA real-time simulation platform, and a simulation analysis verifies the accuracy of the model. This method can improve the simulation scale of an LCC-HVDC system, and enhance the versatility of the LCC-HVDC real-time simulator based on a FPGA.