• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.14 no.5
• /
• pp.30-37
• /
• 2015

The study for enhancing the data transmission rate of the next generation wireless communication system using MIMO system operating in the frequency selective fading environment is currently actively conducted. Mixed signal from each transmitted antennas are received at antennas. The training signal with orthogonal property is needed to separate the mixed signal and enable to estimate channel and time synchronization. In this paper we introduce several training sequences used in MIMO communication system and proposed the modified WeCAN sequence with good auto-correlation property in interested area. We compared auto-correlation property of each sequence via simulation and compared the performance of sequences in doppler shift and multipath fading channel.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.190.2-190.2
• /
• 2016

메탄은 변환을 통해 아세틸렌 및 수소와 같은 에너지 생산에 보다 유용한 기체를 얻을 수 있다. 메탄의 열분해 온도는 약 1,200 K로 알려져 있으며, 그 이상의 고온 환경 및 첨가물을 제공한 경우 효과적인 변환을 기대할 수 있다. 이러한 고온 환경 및 화학반응을 제공할 수 있는 시스템으로 열플라즈마 반응로가 있다. 일반적인 열플라즈마는 아크 방전이나 고주파 유도결합 방전으로 플라즈마 발생기에서 발생시킨 이온화된 열유체로 10,000 K 이상의 초고온과 최대 수천 m/s의 특성을 가지고 있다. 본 연구에서는 효율적인 메탄 변환을 위한 저전력 아크 플라즈마 발생기 및 반응로 내부의 온도 및 속도장을 전산모사하여 열유동 특성을 분석하였다. 아크 플라즈마 토치 영역의 전산해석은 전자기적 현상과 고온 열유동의 유체역학적 현상이 함께 작용하므로 기존에 사용되고 있는 전산유체 역학적인 방법론에 전자기적 현상에 대한 보존 방정식이 결합된 자기유체역학(Magnetohydrodynamic, MHD)방법을 이용하였고, 반응기 내부의 복잡한 열유동은 안정적인 계산이 가능한 상용 전산 유체역학(Computational Fluids Dynamics, CFD) 코드를 MHD 코드를 이용한 전산해석 결과 및 고온 물성치와 결합하여 해석하였다. 전산해석에 사용된 운전 변수로는 방전기체인 아르곤과 수소의 전체 유량을 45 L/min 으로 고정하고 수소의 비율을 0%, 6%, 12.5%, 20%로 하였으며, 각 유량 조건에서 입력 전력을 0.7 ~ 2.5 KW로 변화시켜 전체 15종의 운전조건에 따른 전산해석을 수행하여 각각의 운전변수에 따라 입력전력 기준 오차 1 ~ 28%에 해당하는 결과를 도출하였다. 본 연구를 통해 개발된 전산해석 방법을 이용하여 다양한 조건에서 아크 플라즈마 반응로 내부의 온도 및 속도장에 대한 전산해석 결과를 제시하였고, 효율적인 메탄 변환 공정을 개발하기 위한 아크 플라즈마 반응로의 설계조건 및 운전 조건을 제시할 수 있는 기반을 확보하였다.

• Journal of the Korea Convergence Society
• /
• v.8 no.12
• /
• pp.291-298
• /
• 2017

In recent years, the increase of secondary controls within vehicles requires a mechanism to integrate various controls into a single device. This paper presents control performance of an integrated magnetorheological (MR) haptic device which can adjust various in-vehicle comfort instruments. As a first step, the MR fluid-based haptic device capable of both rotary and push motions within a single device is devised as an integrated multi-functional instrument control device. Under consideration of the torque and force model of the proposed device, a magnetic circuit is designed. The proposed MR haptic device is then manufactured and its field-dependent torque and force are experimentally evaluated. Furthermore, an inverse model compensator is synthesized under basis of the Bingham model of the MR fluid and torque/force model of the device. Subsequently, haptic force-feedback maps considering in-vehicle comfort functions are constructed and interacts with the compensator to achieve a desired force-feedback. Control performances such as reflection force are experimentally evaluated for two specific comfort functions.

• Journal of the Korea Computer Industry Society
• /
• v.8 no.1
• /
• pp.29-40
• /
• 2007

In this study, current status of technology and realities of usage on wireless Internet for educational applications were examined, and based on related studies and case analysis, 'Matrix OX Quiz' that can be applied at present time was designed and built. Main characteristics of this system are as below: Firstly, an attempt was made to achieve educational effect by offering educational contents that are suitable for wireless Internet era, breaking away form limitations on time and space with previous wired Internet. Secondly, mobile phone was selected as the wireless Internet terminal considering the current wireless Internet usage environment and technology, and improved convenience by supporting WAP form Markup language used by SK telecommunications with the most enrollment at present. Thirdly, self-directed learning capability of students can be improved through lessons utilizing wireless Internet. Especially, responsibilities for teaming can be increased through lessons utilizing wireless Internet, and abilities needed for solving immediate problems can be developed. Therefore, the educational contents built in this study should have sufficient educational effects if wireless Internet becomes widely spread and most students can easily use it in near future.

• Korean Journal of Occupational Health Nursing
• /
• v.22 no.3
• /
• pp.228-239
• /
• 2013

Purpose: This study aims to assess the effects of psychosocial work environment and self-efficacy on stress, depression, and burn-out among office workers. Methods: Survey data were collected from 331 office workers who worked in one workplace from April 10 to 30, 2012. The impact of psychosocial work environment and self-efficacy on stress, depression, and burn-out was analyzed with hierarchical multiple regression using SAS version 9.3. Results: Work-family conflicts and emotional demands were identified as main factors influencing mental health. Other work environment factors influencing mental health were role clarity for stress, possibilities for development, meaning-of work, social support-from supervisors and job insecurity for depression, and social community at work for burn-out. Self-efficacy was correlated with most psychosocial work environment and factor with independent influence on stress and depression. The final models including general characteristics, psychosocial work environment, and self-efficacy accounted for 34%, 44%, and 36% for stress, depression, and burn-out respectively. Conclusion: To promote mental health in office workers, there is a need to decrease work-family conflicts and emotional demands and to improve work organization and job contents, social support, and self-efficacy.

• The Journal of the Korea Contents Association
• /
• v.17 no.2
• /
• pp.55-70
• /
• 2017

In order to understand job burnout, it is necessary to consider not only the working environment according to the market environment but also the social situation of the team or the organization. This study analyzed the effects of job demands and job resources on job burnout based on JD-R theory. In other words, the team-level variables, servant leadership and HRM control types, were tested for the effect of moderating the individual workload, emotional labor and job burnout. The results of empirical analysis showed that the higher the self-efficacy, the less job burnout, whereas the higher the workload and emotional labor, the more job burnout. Second, the more positive the team level input and result oriented HRM are, the less positive regression relation of workload and job burnout is. Finally, it was found that the intensity of the regression relation of negative self-efficacy and job burnout was amplified in the team with servant leadership.

• The Journal of the Korea Contents Association
• /
• v.15 no.8
• /
• pp.625-641
• /
• 2015

Recent research shows that emotion is closely related to memory and learning. Although a growing number of educators have high interest in affective aspects of learning processes and outcomes, there are few studies to investigate systematically instructional strategies and learning environments based on learners' emotion. Despite the efforts to understand the role of emotion and to facilitate positive emotion for meaningful learning in face-to-face and online environments, it is still a challenging issue to measure emotion in a valid and reliable way. To implement emotion-based education, it is essential to overcome the limitation of self-report surveys on emotion, which rely on the memory of learners. The current study surveyed emotion measurement tools, which are recently developed in education and other domains, in terms of self-report, neurophysiology, and behavioral responses. This study also discussed how emotion measurement tools can be used in authentic learning and teaching situations. Particularly, this study focused on cutting-edge technologies that would enable educators to collect and analyze learners' emotion easily in real-world contexts. This study will contribute to the research about the role of emotion in education and the design of adaptive learning environments that consider the change of learners' emotion.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.1
• /
• pp.398-407
• /
• 2018

This study examined the concept of nursing student's ethical competence. The concept analysis process by Walker and Avant was used to clarify the meaning of nursing student's ethical competence. As a result, the concept of nursing student's ethical competence was defined in terms of ethical sensitivity, ethical judgement, willingness to implement ethical behavior, and execution power of ethical behavior. Self-understanding, supportive environment, experience of ethical conflict and experience of ethical education can be seen as antecedents for nursing student's ethical competence. The nursing student's ethical competence results in nursing professionalism, satisfaction with nursing, and patient safety. The results of the analysis establish a basis for an instrument to evaluate nursing student's ethical competence. This will guide educators, as well as managers in healthcare, to develop an education program for improvement nursing student's ethical competence.

• KIISE Transactions on Computing Practices
• /
• v.23 no.8
• /
• pp.481-486
• /
• 2017

There are many scientists who want to perform experiments in a cloud environment, and pay-per-use services allow scientists to pay only for cloud services that they need. However, it is difficult for scientists to select a suitable set of resources since those resources are comprised of various characteristics. Therefore, classification is needed to support the effective utilization of cloud resources. Thus, a dynamic resource clustering method is needed to reflect the characteristics of the application that scientists want to execute. This paper proposes a resource clustering analysis method that takes into account the characteristics of an application in a hybrid cloud environment. The resource clustering analysis applies a Self-Organizing Map and K-means algorithm to dynamically cluster similar resources. The results of the experiment indicate that the proposed method can classify a similar resource cluster by reflecting the application characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.2109-2116
• /
• 2015

This study aimed to identify the influencing factors on nicotine dependency of middle school smokers and to provide the basic data for the effective smoking cessation program. Data were collected from May 3 to July 26 in 2013 by self-reported questionnaires. The subjects of this study were 202 middle school smokers in D city. For data analysis, SPSS 18.0 and AMOS 18.0 was used to calculate Percentage, mean, Standard deviation, ANOVA, Scheffe test, Pearson's correlation coefficient and Path analysis. The results showed that smoking reinforced factors, social environment factors, self-efficacy and impulsivity were significantly influenced on the nicotine dependency directly and indirectly. Therefore, it is necessary to include intervention of smoking reinforced factors, social environment factors, self-efficacy and impulsivity to develop smoking cessation program for smoking in middle school students.