• 응용통계연구
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• 제25권4호
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• pp.621-632
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• 2012

Recurrent event data can be easily found in longitudinal studies such as clinical trials, reliability fields, and the social sciences; however, there are a few observations that disappear temporarily in sight during the follow-up and then suddenly reappear without notice like the Young Traffic Offenders Program(YTOP) data collected by Farmer et al. (2000). In this article we focused on inference for a cumulative mean function of the recurrent event data with these incomplete observation gaps. Defining a corresponding risk set would be easily accomplished if we know the exact intervals where the observation gaps occur. However, when they are incomplete (if their starting times are known but their terminating times are unknown) we need to estimate a distribution function for the terminating times of the observation gaps. To accomplish this, we treated them as interval-censored and then estimated their distribution using the EM algorithm proposed by Turnbull (1976). We proposed a nonparametric estimator for the cumulative mean function and also a nonparametric test to compare the cumulative mean functions of two groups. Through simulation we investigated the finite-sample performance of the proposed estimator and proposed test. Finally, we applied the proposed methods to YTOP data.

• 대한의용생체공학회:의공학회지
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• 제29권6호
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• pp.443-450
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• 2008

The purpose of this study is to measure both ECG and BCG(Ballistocariograph) signal of a subject on moving or resting wheelchair and detect the heart rate and respiratory rate and transmit an event message to remote server on emergent situation. To acquire ECG and BCG data, amplifier circuits were composed to be suitable for their characteristics. The output signals were converted to digital data and stored in bio-signal archiving media(SD card). CDMA module was used to transmit the event data on ECG electrode detachment and the received data was monitored by the developed C# application program. 5 volunteers participated in the experiment to evaluate the validity of the developed device. When the event occurs in each subject, 48 Kbyte data, stored for 32 seconds from that point, was transmitted to remote server through CDMA cellular phone network correctly. The received data of ECG, BCG, and 3-axial acceleration could be archived in server and the heart rate and respiratory rate could be measured and analyzed. The developed device in this study could acquire the ECG and BCG data of subjects on wheelchair simultaneously and measure their heart rate and respiratory rate. In addition, event data was verified to be transmitted to remote server without any errors.

• 한국정보과학회논문지:데이타베이스
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• 제37권6호
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• pp.324-332
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• 2010

실시간 임베디드 센서 네트워크 시스템에서의 이벤트 감지는 대부분 현실세계에서 수집된 센서 데이터들의 조합에 기반한다. 이에 최근에 이루어진 연구들에선 센서 데이터들을 수집, 집계하는 낮은 수준의 다양한 메커니즘들을 제안하였다. 그러나 실시간에서 연속적으로 발생하는 복잡한 이벤트들의 감지와 다양한 종류의 센서들로부터 입력되는 실시간 데이터의 처리를 위한 시스템에 대한 솔루션은 보다 많은 연구를 필요로 한다. 즉, 경량의 데이터 혼합이 가능하고 많은 컴퓨팅 자원을 필요로 하지 않는 실시간 이벤트 감지 기법이 필요하다. 이벤트 감지 프레임워크는 실시간 모니터링과 센서 데이터의 도착으로 일어나는 데이터 융합 메커니즘을 통하여 적시성과 임베디드 센서 네트워크의 자원 요구량을 감소시킬 수 있는 잠재력을 지니고 있다. 또한 임베디드 센서 네트워크 시스템이 신뢰성을 지닐 수 있도록 하기 위한 기반 기술인 프라이버시를 보장할 수 있는 익명화 기술을 설명한다.

• Journal of Sport and Applied Science
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• 제8권1호
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• pp.11-17
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• 2024

Purpose: The purpose of the study was to understand a trend of esports in terms of gamers' and fans' perceptions toward esports using social big data. Research design, data, and methodology: In this study, researchers first selected keywords related to esports. Then a total of 10,138 buzz data created at twitter, Facebook, news media, blogs, café and community between November 10, 2022 and November 19, 2023 were collected and analyzed with 'Textom', a big data solution. Results: The results of this study were as follows. Firstly, the news data's main articles were about competitions hosted by local governments and policies to revitalize the gaming industry. Secondly, As a result of esports analysis using Textom, there was a lot of interest in the adoption of the Hangzhou Asian Games as an official event and various esports competitions. As a result of the sentiment analysis, the positive content was related to the development potential of the esports industry, and the negative content was a discussion about the fundamental problem of whether esports is truly a sport. Thirdly, As a result of analyzing social big data on esports and the Olympics, there was hope that it would be adopted as an official event in the Olympics due to its adoption as an official event in the Hangzhou Asian Games. Conclusions: There was a positive opinion that the adoption of esports as an official Olympic event had positive content that could improve the quality of the game, and a negative opinion that games with actions that violate the Olympic spirit, such as murder and assault, should not be adopted as an official Olympic event. Further implications were discussed.

• ETRI Journal
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• 제31권4호
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• pp.463-465
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• 2009

In this letter, we present an event stream processing system that can evaluate a pattern query for a data sequence with predicates. We propose a pattern query language and develop a pattern query processing system. In our system, we propose novel techniques for run-time aggregation and negation processing and apply our system to stream data generated from vehicles to monitor unusual driving patterns.

• 산업융합연구
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• 제1권1호
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• pp.127-142
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• 2003

This Study examines the implications for event studies using the daily stock data. The output present the event study results. The event period is defined from 30 days before through 30 days after the event date, and is broken into four "windows" for abnormal return cumulation: the pre-event period, days -30 through -2; dajys -1 and 0, a period commonly investigated for the immediate impact of the event; and the post-event period, days +1 through +30. It shows how firm's information offerings affect the price process and consequent issues. The Patell Z test is an examples of a standardized abnormal return approach, which estimate a separate standard error for each security-event and assumes cross-sectional independence. The generalized sign test adjusts for the fraction of positive abnormal returns in the estimation period instead of assuming 0.5.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1165-1171
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• 2017

The traditional form of parallelism in Monte Carlo particle transport simulations, wherein each individual particle history is considered a unit of work, does not lend itself well to data-level parallelism. Event-based algorithms, which were originally used for simulations on vector processors, may offer a path toward better utilizing data-level parallelism in modern computer architectures. In this study, a simple model is developed for estimating the efficiency of the event-based particle transport algorithm under two sets of assumptions. Data collected from simulations of four reactor problems using OpenMC was then used in conjunction with the models to calculate the speedup due to vectorization as a function of the size of the particle bank and the vector width. When each event type is assumed to have constant execution time, the achievable speedup is directly related to the particle bank size. We observed that the bank size generally needs to be at least 20 times greater than vector size to achieve vector efficiency greater than 90%. When the execution times for events are allowed to vary, the vector speedup is also limited by differences in the execution time for events being carried out in a single event-iteration.

• Journal of the Korean Data and Information Science Society
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• 제25권2호
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• pp.327-336
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• 2014

재발 사건 자료란 연구대상이 같은 종류의 사건을 반복적으로 경험할 때 발생하는 자료이다. 이러한 재발 사건은 사회과학, 자연과학, 공학, 의약학 등 다양한 분야에서 나타날 수 있다. 재발 사건자료를 분석할 때 연구자의 관심에 따라 사건 발생시간이나 사건 발생간의 소요시간을 이용하여 분석할 수 있다. 이 논문에서는 사건 발생시점간의 소요시간을 이용하여 불완전한 관측을 가진 재발 사건자료를 분석하고자 한다. 이 자료의 특징은 일부 관측대상들이 일정기간 동안 연구에서 제외되는 관측틈을 갖는다는 것이다. 이 때 관측틈은 불완전한 형태로 나타나게 되는데 그 이유는 관측틈의 시작시점은 알고 있지만 종료시점은 알 수 없기 때문이다. 이러한 미지의 종료시점을 추정하기 위해서 구간 중도 절단 방법이 적용된다. 따라서 종료시점이 추정된 후 프레일티를 포함한 회귀모형을 적용하여 공변량이 사건 재발에 미치는 영향을 알아볼 수 있다. 또한 제안한 방법을 실제자료에 적용하여 관측틈을 고려한 경우와 고려하지 않은 경우를 비교하고자 한다.

• 한국통신학회논문지
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• 제34권11B호
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• pp.1200-1206
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• 2009

본 논문에서는 유비쿼터스 센서네트워크(USN, Ubiquitous Sensor Network) 환경을 위한 에너지 효율적 상황인 식 매체접근제어(MAC, Medium Access Control) 프로토콜을 제안한다. 제안한 CASMAC(Context Aware Sensor MAC)은 상황정보를 이용하여 에너지 효율적으로 동작한다. CASMAC의 동작원리는 사전에 예측 가능한 상황을 시나리오로 작성하여 설정한 상황정보를 서버에 저장하며, 특정 센서 노드에서 이벤트가 발생할 경우, 그 이후부터 3회의 샘플 데이터를 서버로 전송한다. 서버는 전송 받은 샘플 데이터를 기 설정된 상황정보에 따라 처리한다. 만약 샘플 데이터가 이벤트로 처리되면, 서버는 해당 노드로 지속적인 데이터 전송 요청 신호를 보내 데이터를 전송 받고, 데이터 전송을 더이상 원하지 않으면 데이터 전송 중지 요청 신호를 보낸다. 또한 이벤트가 아니라고 처리할 경우에는, 무응답을 통해 샘플 데이터를 무효 처리한다. CASMAC의 성능 분석을 위해, 에너지 소모 테이블을 작성하여 에너지 소모 모델을 도출하였고, 모의 실험을 수행하였다. 그 결과 SMAC 대비 약 5.7 퍼센트의 에너지 소모 감소를 통한 성능 개선 효과를 얻었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.807-825
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• 2020

In recent years, business environments have become more complex; therefore, enterprises must be capable of responding flexibly and agilely. For these purposes, effective enterprise systems service monitoring and early decision making based on the same, emerge as core competency of the enterprise. In addition, enterprise system techniques that filter meaningful data are needed to event processing. However, the existing study related with this is nothing but discovering of service faults by monitoring depending upon API of BPEL engine or middleware, or is nothing but processing of simple events based on low-level events. Accordingly, there would be limitations to provide useful business information. In this study, we present an extended event processing model that enables delivery of more valuable and useful business information through situation detection. Primarily, the event processing architecture in an enterprise system is proposed as a definite approach, and then define an event meta-model suitable for the proposed architecture. Based on the defined model, we propose the syntax and semantics of the elements that make up the event processing language include various and progressive event operators, the rules, complex event pattern, etc. In addition, an event context mechanism is proposed to analyze more delicate events. Finally, the effectiveness and applicability of proposed approach is presented through a case study.