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강제적 사용 환경에서 정보시스템 지속에 대한 상황요인의 영향에 관한 연구
김대환(Dae Hwan Kim),한정희(Jung Hee Han),장활식(Hwal Sik Chang) 한국경영학회 2010 經營學硏究 Vol.39 No.2
The purpose of this study is to investigate the value of contingency factors on post-adoptive beliefs that influence a user’s satisfaction and intention in the context of mandatory continued IS usage. It is certain that long-term viability of an IS and its eventual success depend on its continued use rather than its first-time use(Bhattacherjee, 2001b). If management wants to promote continued IS usage behavior of users, it is necessary to understand what drives it. We are great on the two existing circumstances. First, when does the IS usage behavior really begin? When a user does decide to accept it? Or when the user uses it to carry out assigned work tasks? Because of the path-dependent nature of IT adoption and use processes in general(Rogers, 2003), post-adoptive behavior must be framed within this larger context. However, we only focus on post-adoptive behavior, because obvious distinctions have been observed between pre-adoptive and post-adoptive beliefs and behaviors(Karahanna et al., 1999; Oliver, 1980). TAM has primarily focused on adoption under the implicit assumption that users' attitude and intention are mainly determined by pre-adoptive cognitive beliefs. It does not reveal what is really driving continued usage behavior above and beyond the antecedents derived from TAM researches. Alternatively, the expectation-confirmation model of IS continuous (ECM-IS continuous)(by Bhattacherjee, 2001b) based on a solid theoretical foundation that focuses on an individual’s psychological motives during post-adoption, and it has been successfully adapted to the IS continuous context. As mentioned reasons, we decided to use Bhattacherjee’s model instead of TAM as the departure of our study. Second, this study focuses on the environments where usage is mandatory. In today’s organizations, tasks are increasingly depending on work systems, forcing their members to use the systems to increase their job productivity. The contingency approach suggests that a number of contextual variables influence the performance of IS; the better the 'fit' between these variables and the design and use of the IS, the better the IS performance(Weill and Olson, 1989). Previous researches have in particular emphasized the task-technology fit, job relevance, or compatibility with work in the context of IS mandatory(Kim et al., 2007). Task characteristics have a huge effect on a user’s satisfaction on their IS and success of the system (Raymond and Bergeron, 1992; Sanders and Courtney, 1985). In addition, in IS field it has been identified that individual factors can be as important as task factors for the success of IS. User characteristics are also found to affect the post-adoptive beliefs. We consider users’ individual characteristic as well as work task characteristic as contingent factors in the context of mandatory IS usage. Accordingly, this paper proposes a contingency approach relating selected task characteristics and user characteristics on ECM-IS continuous in mandated environments. In this research, task characteristics were include in task variability and analyzability, and user characteristics were include system-specific self-efficacy and user education and training, which affects to form users’ cognitive belief such as expectation-confirmation and perceived usefulness during post-adoption. This paper attempts to expand the set of contingency factors in the ECM-IS continuous, in order to confirm the application of the ECM-IS continuous in IS mandatory usage context. The expanded ECM-IS continuous, incorporating the contingency factors of task variability, task analyzability, system-specific self-efficacy, and user education and training, was empirically validated with data collected from a field survey of 169 existing users of e-customs system. We used partial least square(PLS) to examine the reliability and validity of the measures, and to analyze this extended ECM-IS continuous. We chose PLS for two reasons. First, our model has form
김대환(Dae Hwan Kim),박정우(Jung Woo Park),김영한(Young Han Kim) 한국청정기술학회 2010 청정기술 Vol.16 No.1
가소제 등의 중간원료로 사용하는 2-에틸헥산올의 농축공정에 기존의 2 탑 증류 시스템 대신 에너지 절약형 증류탑인 열복합 증류탑을 사용할 때의 에너지 절감효과를 시뮬레이션을 통하여 계산하였다. 기존의 2탑증류방식에 비해 약 41%의 에너지 절감효과가 있음을 계산의 결과로부터 알 수 있었으며, 에너지 절감의 원인을 증류곡선으로 설명하였다. 또, 기존 공정 대신 열복합 증류탑을 사용하면 증류탑의 운전비용뿐만 아니라 설비비의 절감도 가능한 추가적인 이득이 있다. The concentration process of 2-ethyl hexanol used for the intermediate material in the production of plasticizer is examined for the energy conservation of energy-efficient distillation system instead of the conventional two column system through numerical simulation. Some 41 % of energy conservation is expected from the proposed system, and its conservation principle is explained with column profiles. In addition, not only the operating cost but also investment cost can be reduced for the additional benefit of the column application when the thermally coupled distillation is implemented.
국소 부위 고온 및 저온 스트레스가 안정 시 및 운동 시 온냉감 민감도 및 중성역에 미치는 영향
김대환 ( Dae-hwan Kim ),한진희 ( Jean-hee Han ),장민혁 ( Min-hyeok Jang ),김정현 ( Jung-hyun Kim ) 한국운동생리학회 2021 운동과학 Vol.30 No.4
PURPOSE: The primary objective of this study was to investigate the effects of local cold and heat stimuli on cutaneous thermal sensitivity and inter-threshold zone at rest and during exercise. METHODS: Cutaneous warm and cold thresholds were measured on two body regions (forehead and hand) in three types of local thermal stress environments (neutral, heat, cold) using a method of limit in sixteen young, healthy male subjects (25.44±2.28 years) at rest and during exercise. RESULTS: The results showed that the thermal inter-threshold zone was wider on the hand than on the forehead under thermal stress conditions at rest and during exercise. The thermal inter-threshold zone on both body regions widened with exercise (p<.05). Exercise significantly blunted both the warm and cold sensitivity in the forehead (p<.05), but only cold sensitivity in the hand (p<.05). Moreover, the thermal inter-threshold zone on both the forehead and hand became significantly wider when heat or cold stress was applied to the local body region (p<.001). In the forehead, warm and cold sensitivity were significantly blunted in both heat and cold stress environments (p<.05), whereas in the hard they were significantly blunted only in the heat stress environment (p<.01). CONCLUSIONS: In conclusion, the present study showed that the forehead is more sensitive to both warm and cold stimuli than the hand, regardless of thermal stress or exercise. Furthermore, the thermal inter-threshold zone on both the forehead and the hand widened with exercise and local thermal stimuli.
김대환 ( Dae Hwan Kim ),윤경한 ( Kyeong Han Yoon ) 대한피부과학회 2002 대한피부과학회지 Vol.40 No.4
Primary cutaneous plasmacytoma is a rare cutaneous B cell lymphoma characterized by monoclonal proliferation of mature plasma cells in the skin without systemic involvement. Although a significant proportion of patients, especially with multiple lesions, went on to develop systemic disease with a poor prognosis. the abnormal clone of plasma cells may arise in the skin and never progress to multiple myeloma involving the bone manow in number of patients. We report a case of primary cutaneous plasmacytoma and review dam published in the literature. A 19-year-old man developed multiple 0.2 to 0.5an sized erythematous grouped papules on his posterior neck for 4 years. Histopathologic examination represented superficial and deep interstitial and nodular dense infiltration of plasma cells showing monoclonal expression of immunoglobulin lambda light chain. F-I8 FDG concidence PET(CoDe-PET) scan and serum electrophoresis were within normal limit. Any systemic disease has not developed for 6 months after diagnosis.
304 스테인리스강의 300℃에서 저주기 피로수명 증가
김대환 ( Dae Whan Kim ),한창희 ( Chang Hee Han ),이봉상 ( Bong Sang Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 2009 대한금속·재료학회지 Vol.47 No.7
Tensile, low cycle fatigue, and fatigue crack growth rate tests were conducted at RT and 300℃ for type 304 stainless steel. Tensile was tested under displacement control and low cycle fatigue was tested under strain control. Fatigue crack growth rate test was conducted under load control and crack was measured by DCPD method. Yield strength and elongation decreased at 300℃. Dynamic strain aging was not detected at 300℃. Low cycle fatigue life increased but fatigue strength decreased at 300℃. Fatigue crack growth rate increased at 300℃. Dislocation structures were mixed with cell and planar and did not change with temperature. Grain size did not change but plastic strain increased at 300℃. Strain induced martensite after low cycle fatigue test increased at RT but decreased at 300℃. It was concluded that the increase of low cycle fatigue life at 300℃ was due to the decrease of strain induced martensite at which crack was initiated.
에너지 데이터 수집 및 관리 플랫폼 개발과 구축에 대한 연구
김범주(Kim Beom-Joo),김대환(Kim Dae-Hwan),윤경희(Yoon Kyung-Hee),한정훈(Han Jeong-Hoon) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
본 논문은 최근 우리나라에서 진행 중인 한국형 뉴딜 중 그린뉴딜 정책, 그리고, 전 세계적인 4차 산업혁명에 따른 빅데이터 활용에 있어 생활에 밀접한 데이터인 에너지 데이터를 활용한 인프라 구축과 서비스 모델 개발에 대한 내용을 담고 있다. 현재 우리나라는 원격검침시스템을 통한 국가 단위 에너지 데이터 수집을 진행하고 있으나, 데이터의 활용도가 낮은 상황이다. 이에 따라, 에너지 데이터의 정보로서 가치를 높이고, 기존 공급관리에서 수요관리 방식으로의 에너지 효율화 정책 전환에 따른 에너지 빅데이터 활용에 대한 수요가 지속적으로 발생하고 있다. 본문을 통해 현재 누리플렉스에서 진행 중인 가정용 스마트전력 플랫폼 사업과 에너지 데이터 활용 서비스 플랫폼 개발 기술의 기본적인 이해를 통해 향후 다양한 데이터를 융합한 서비스가 나타나고, 이를 통한 시장 활성화를 기대하는 바이다.