• 대한인간공학회지
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• 제32권6호
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• pp.535-540
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• 2013

Objective: The aim of this study is to evaluate the effectiveness and efficiency of causal links between various error causes in human error analysis. Background: As finding root causes of human error in safety-critical systems is often a cognitively demanding and time-consuming task, it is particularly necessary to develop a method for improving both the quality and efficiency of the task. Although a few methods such as CREAM have suggested causal linking between error causes as a means to enhance the quality and efficiency of human error analysis, no published research to date has evaluated the performance of the causal links. Method: The performance of the CREAM links between error causes were evaluated with 80 railway accident investigation reports from the UK. From each report, errorneous actions of operators were derived, and for each error, candidate causes were found by following the predefined links. Two measures, coverage and selectivity, were used to evaluate the effectiveness and efficiency of the links, respectively. Results: On average, 96% of error causes actually included in the accident reports were found by following the causal links, and among the total of 121 possible error causes, the number of error causes to be examined further was reduced to one-tenth on average. As an additional result of this work, frequent error causes and frequently used links are provided. Conclusion: This result implies that the predefined causal links between error causes can significantly reduce the time and effort required to find the multiple levels of error causes and their causal relations without losing the quality of the results. Application: The CREAM links can be applied to human error analysis in any industry with minor modifications.

• IMMUNE NETWORK
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• 제11권1호
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• pp.1-10
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• 2011

Interleukin-7 (IL-7) is an essential cytokine for T cells. However, IL-7 is not produced by T cells themselves such that T cells are dependent on extrinsic IL-7. In fact, in the absence of IL-7, T cell development in the thymus as well as survival of naive T cells in the periphery is severely impaired. Furthermore, modulating IL-7 availability in vivo either by genetic means or other experimental approaches determines the size, composition and function of the T cell pool. Consequently, understanding IL-7 expression is critical for understanding T cell immunity. Until most recently, however, the spatiotemporal expression of in vivo IL-7 has remained obscured. Shortage of such information was partly due to scarce expression of IL-7 itself but mainly due to the lack of adequate reagents to monitor IL-7 expression in vivo. This situation dramatically changed with a recent rush of four independent studies that describe the generation and characterization of IL-7 reporter mice, all utilizing bacterial artificial chromosome transgene technology. The emerging consensus of these studies confirmed thymic stromal cells as the major producers of IL-7 but also identified IL-7 reporter activities in various peripheral tissues including skin, intestine and lymph nodes. Strikingly, developmental and environmental cues actively modulated IL-7 reporter activities in vivo suggesting that IL-7 regulation might be a new mechanism of shaping T cell development and homeostasis. Collectively, the availability of these new tools opens up new venues to assess unanswered questions in IL-7 biology in T cells and beyond.

• Journal of the Korean Data and Information Science Society
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• 제24권4호
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• pp.847-856
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• 2013

본 논문에서는 모수적과 비모수적 엔트로피 추정량들에 기초한 정규분포에 대한 적합도 검정을 다룬다. 정규분포의 엔트로피에 대한 모수적 추정량으로 사용할 최소분산비편향추정량을 유도한다. 이 추정량과 대립가설 하에서의 자료생성분포에 대한 비모수적 엔트로피 추정량으로 표본엔트로피와 이것의 변형된 추정량들을 이용하여 검정통계량들을 구축했고 이 검정통계량들을 사용하는 새로운 엔트로피 기반 적합도 검정들을 제시한다. 제안한 검정들의 기각값들을 모의실험을 통해 추정해서 표의 형태로 제시한다. 성능의 조사를 위해 수행한 모의실험에서 제안한 검정들이 기존의 Vasicek (1976) 검정보다는 더 좋은 검정력을 가지는 것으로 나타난다. 응용에서 새로운 검정들이 정규성 검정을 위한 경쟁적인 도구로 시용될 수 있을 것으로 기대된다.

• Child Health Nursing Research
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• 제5권2호
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• pp.136-150
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• 1999

The subjects, under 18 old, 2,694 children who visited ER during 1998, were surveyed by the Triage and other statitical data. The results were as follows 1. The male to female ratio was 1.7 : 1, and the toddler(1-4 old) was the majority. 2. Triage ; critical 1.3%, acute 14.6%, urgent 29.5%, nonemergent 54.6%. 3. The reasons of visiting ER ; 1) The children had diseases(46.5%), injury (36.9%), TA(5.6%) and toxication(1.0%). 2) In diseases, male to female ratio was 1.5 : 1 and in injury, male to female was 2 : 1. 3) Among the children having in TA, 12-18 old groups was the majority(34.9%). 4. The time of visiting : the 20:00 - 22:00 was the majority(16.9%). 5. By monthly and seasonal distribution ; Jan. (9.7%), Mar. and May(9% respectively, Dec. and July(6.7%) respectively. The children who visted ER in spring and autumn showed higher portion than those of summer and winter. 6. Results ; admission(27.4%), discharge(68.4%), operations(2.8%), and DOA and DAA(0.4%), The mortality of the infancy and toddler groups was 83.3%. The infancy group showed the highest rate of admission. 7. The time of staying in ER ; 1-2 hrs was the major group(23.3%) and the average was 4.6 hours. 8. By clinical departments ; Ped. was 34.4%, PS was 20.8%, Dental Surgery was 10.3% and Dermatology was 0.9%. 9. The types of visting ; the group who visited by themselves was 80%, transfer from the primary and secondary clinic was 17% and OPD was 3.0%. 10. The traffic means . by the own cars and taxi were 87.6%, by hospital ambulance was 6.1% and by 119 ambulance was 4.3%.

• 수면정신생리
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• 제8권2호
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• pp.138-143
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• 2001

Sleepiness is associated with many different conditions and, as a neglected topic, it can be the cause of serious psychological and social disadvantages. In the aspect of learning, additional problems may arise from poor progress in school caused by the effect of sleepiness on concentration, memory, and other cognitive functions. Narcolepsy is by no means the most common cause of excessive sleepiness. Nonetheless, it is not a rarity, especially in young people. The non-specific nature of early features of narcolepsy, combined with very limited awareness that the condition can start in various ways, leads to many misinterpretations. Misinterpretation of narcolepsy symptoms is not confined to the medical profession. Teachers may well be critical of a student with narcolepsy because of their perception of narcolepsy symptoms as laziness, poor motivation, or difficult behavior and dull learning ability. Inappropriate reactions by parents, teachers, and peers, based on misinterpretation of narcolepsy symptoms or the patient's reactions to them, make a difficult situation worse. Especially in Korea, where schooling is focused on college entrance examinations, the problem is very serious and intensified by inappropriate or delayed diagnosis and treatment. Therefore, psychiatrists should be aware that narcolepsy in young adolescents is not rare and that they need to be familiar with its clinical features in both its classic and less obvious forms. Narcolepsy should be suspected if a adolescent's excessive sleepiness can not be explained in other ways. Therefore, we report on two patients who portray the tendency of dull learning ability and are mistaken as idle students. We diagnosed narcolepsy through polysomnography and multiple sleep latency testing. We treated the students with methylphenidate and pemolin. The students showed improvement in learning ability and were able to adapt better to school.

• 대한지리학회지
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• 제42권2호
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• pp.280-294
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• 2007

이 논문은 싱가포르 정부가 어떻게 싱가포르의 장소마케팅을 위한 수단으로 "세계도시" 이미지 전략을 사용하는가를 탐구하는 것을 목적으로 한다. 1990년대부터 싱가포르는 그 자신을 "창조적이고", "문화적으로 활기차며", "코스모폴리탄"한 세계도시라고 이미지화하기 위한 장소마케팅 전략을 추진해 왔고, 이를 위해 여러 다양한 문화, 관광, 공간 정책수단들을 사용하였다. 이 논문에서 필자는 싱가포르 정부의 이러한 이미지화 전략은 싱가포르 경제를 지식기반 경제로 전환하려는 경제재편 프로그램과 밀접히 관련되며, 이는 장소마케팅을 통해 국제적인 지식 노동자들을 끌어들이는 것이 경쟁력과 혁신을 이끌어내는데 핵심적이라는 믿음에 기인한다. 이와 더불어 이 논문은 이러한 이미지 전략의 한계에 대해서도 논하는데, 특히 싱가포르 사회에서 어떻게 글로발과 로칼 간의 긴장이 증가하고 있는지, 그리고 어떻게 싱가포르의 권위적이고 하향식의 통치체제로 인해 진정한 의미의 "문화적으로 활기한" 환경을 조성하는데 제약이 생기는지 살펴볼 것이다.

• 한국통신학회논문지
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• 제34권9C호
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• pp.848-854
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• 2009

이동체에 대해서 위성을 이용한 통신 방식을 규정하고 있는 DVB-SSP 표준화에서는 physical layer 와 upper layer 의 두 단계로 부호화 및 복호화를 한다. 수신단에서 physical layer의 복호 방식인 LDPC 복호후 upper layer의 erasure RS 복호를 위해, CRC 검사를 수행하여 수신된 데이터에서 1 bit 의 오류에도 IP 패킷 모두를 삭제함으로써 복호시 비효율성을 나타낼 수 있다. 따라서 본 논문에서는 기존의 CRC 방식을 그대로 수용하되 오류능력 범위 한계에 들어오면 e-RS 복호기를 이용하여 복호하며, 오류 한계 범위를 벗어나면 삭제 시키지 않고 수신된 심볼 자체를 이용하여, RS 복호기를 이용하는 복호 방식을 혼합하는 혼합형 복호알고리즘을 제안하며, 이를 가우시안 채널환경과 TI 채널환경에서 시뮬레이션 하여 기존의 CRC 방식과 비교하였다.

• Smart Structures and Systems
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• 제17권6호
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• pp.917-933
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• 2016

In a prestressed concrete bridge, the magnitude of the prestress force (PF) decreases with time. This unexpected loss can cause failure of a bridge which makes prestress force identification (PFI) critical to evaluate bridge safety. However, it has been difficult to identify the PF non-destructively. Although some research has shown the feasibility of vibration based methods in PFI, the requirement of having a determinate exciting force in these methods hinders applications onto in-service bridges. Ideally, it will be efficient if the normal traffic could be treated as an excitation, but the load caused by vehicles is difficult to measure. Hence it prompts the need to investigate whether PF and moving load could be identified together. This paper presents a synergic identification method to determine PF and moving load applied on a simply supported prestressed concrete beam via the dynamic responses caused by this unknown moving load. This method consists of three parts: (i) the PF is transformed into an external pseudo-load localized in each beam element via virtual distortion method (VDM); (ii) then these pseudo-loads are identified simultaneously with the moving load via Duhamel Integral; (iii) the time consuming problem during the inversion of Duhamel Integral is overcome by the load-shape function (LSF). The method is examined against different cases of PFs, vehicle speeds and noise levels by means of simulations. Results show that this method attains a good degree of accuracy and efficiency, as well as robustness to noise.

• 한국분무공학회지
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• 제10권2호
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• pp.1-9
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• 2005

An experimental study was carried out to obtain the fundamental data about the effects of radical ignition on premixture combustion. A CVC(constant volume combustor) divided into the sub-chamber and the main chamber was used. Numerous narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in tile sub-chamber derives the simultaneous multi-point ignition in the main chamber. We have examined the effects of the sub-chamber volume, the diameter and number of passage holes, and the equivalence $ratio({\Phi})$ on the combustion characteristics by means of burning pressure measurement and flame visualization. In a CVC, the overall burning time including the ignition delay became very short and the maximum burning pressure was slightly increased by the radical ignition(RI) method in comparison with those by the conventional spark ignition(SI) method. Combustible lean limit by RI method is extended by ${\Phi}=0.25$ compared with that by SI method. Also, In cases of charging the number and the diameter for the fixed total cross section of the passage holes, combustion period increased significantly at a sub-chamber with a single hole, but those of the other conditions had almost a similar tendency in the sub-chamber with 4 or more holes. regardless of equivalence ratio. Therefore, it was Proved that a critical cross section exists with the number of passage holes.

• 한국컴퓨터정보학회지
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• 제15권1호
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• pp.209-217
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• 2007

우리나라는 중국 일본과 같이 3면이 바다로 둘러 쌓여 있으며, 특히 국가 간 해역의 거리가 근접한 관계로 타국으로 항해를 하거나 조업을 위하여 배타적 경제수역(EEZ: Exclusive Economic Zone)을 설정하여 분쟁의 소지를 담고 있다. 특히 해상에서 발생하는 여러 가지 사고의 경우에는 그 흔적이 해상이라는 특수성 때문에 존재하지 못하는 경우가 많고 어선의 경우 조업일지의 부실기재등으로 국가간 분쟁시 증거자료로 채택할 수 있는 경우는 드물다. 이에 해상 디지털 포렌식은 선박에 설치된 컴퓨터와 정보통신 기술의 순기능을 보호하면서 사고 등에 대한 디지털증거자료를 추출하여 분쟁을 해결하는 증거의 과정을 다루게 된다. 이러한 컴퓨터 등의 디지털증거는 무결성이 훼손된다면, 결정적인 증거가 재판정에서 기각당하거나 국제적으로 분쟁시 증거로서 채택되지 않는다. 본 논문에서는 이 문제점을 해결하는 방안으로 해상 디지털 포렌식을 제안하면서 디지털포렌식자료를 추출하고 이를 입증하는 방법을 제시한다. 이는 해상 교류가 더욱 증가하고 선박장비의 디지털화의 추세에 맞추어 해상에서도 과학수사의 일환으로 활용될 것이며, 이러한 디지털자료를 증거로 국제간의 분쟁 해결의 중요한 열쇠가 될 것이다.