• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권1호
• /
• pp.91-107
• /
• 2014

Device-to-device (D2D) communication is an excellent technology to improve the system capacity by sharing the spectrum resources of cellular networks. Multicast service is considered as an effective transmission mode for the future mobile social contact services. Therefore, multicast based on D2D technology can exactly improve the spectrum resource efficiency. How to apply D2D technology to support multicast service is a new issue. In this paper, a resource allocation scheme based on cognitive radio (CR) for D2D underlay multicast communication (CR-DUM) is proposed to improve system performance. In the cognitive cellular system, the D2D users as secondary users employing multicast service form a group and reuse the cellular resources to accomplish a multicast transmission. The proposed scheme includes two steps. First, a channel allocation rule aiming to reduce the interference from cellular networks to receivers in D2D multicast group is proposed. Next, to maximize the total system throughput under the condition of interference and noise impairment, we formulate an optimal transmission power allocation jointly for the cellular and D2D multicast communications. Based on the channel allocation, optimal power solution is in a closed form and achieved by searching from a finite set and the interference between cellular and D2D multicast communication is coordinated. The simulation results show that the proposed method can not only ensure the quality of services (QoS), but also improve the system throughput.

• 보건행정학회지
• /
• 제7권2호
• /
• pp.89-108
• /
• 1997

The purpose of this study is to investigate drug information sources which influence physician's prescriptions, and to compare the differences of drugh information sources between private practitioners and hospital physicians. In addition, the ultimate goal of this study is to provide better quality of drug information for both groups of physicians through the professional drug information system. 264 physicians, including general practitioners and all types of specialists who were working in hospitals and private clinics in Taejon and Chungnam area, participated in this study which was conducted by mail. The results are summarized as follows ; 1. Both physician groups received drug informations mainly from medical journals, but there were differences in secondary sources of drug information. Namely, hospital physicians got drug information from annual meetings and textbooks, and private practitioners got it from detail men and colleagues. 2. Drug effect was the first consideration for drug selection in both physician groups. But, in the 2nd consideration, private practitioners concerned about the price, insurance and rebates, but hospital physicians were not. 3. Only 9.2% of the private practitioners satisfied with the sufficiency of drug information, whereas 22.0% of hospital physicians satisfied with it. The most insufficient area of information was drug interaction in both groups and 91.9% of the physicians suggested that a professional drug information system should be introduced. 4. Both physician groups had contacted with detail men frequently. However, it was rare for them to contact with a pharmacist. This phenomenon was more severe in the case of private practitioners. 5. Neither physician groups knew very much about drug informatio centers. However, they would be willig to participate if a professional drug information system were established. Also, they indicated that the information most required was drug interaction.

• 대한불안의학회지
• /
• 제6권1호
• /
• pp.65-70
• /
• 2010

Objectives : Indirect contact with trauma may occur when a person empathically listens to detailed descriptions, exposing the person to intense emotional pain from trauma victims. Although less severe than direct trauma, indirectly traumatized persons may experience the same fear, rage, and despair as direct trauma victims. This phenomenon has been variously termed vicarious trauma, traumatic countertransference, burnout, compassion fatigue, and secondary traumatic stress. Using a psychiatric symptoms questionnaires, this study investigated the effects of indirect exposure to co-worker's trauma on the mental health of firefighters who had not directly experienced traumatic events in the previous year. Methods : We administered self-report questionnaires, such as the Impact of Event Scale-Revised (IESR) and Alcohol Use Disorder Identification Test (AUDIT), to firefighters working at two fire stations in a metropolitan city. We analyzed 188 of 232 collected surveys, after excluding falsely entered data (28 cases) and questionnaires by directly-traumatized victims (16 cases). Results : Alcohol consumption and posttraumatic stress disorder (PTSD) symptoms, as determined by the AUDIT and IES-R, were significantly higher in the indirectly-traumatized group. The ratio of high-risk members scoring higher than 23 in IES-R was larger in the indirectly traumatized group, although this was not statistically significant. Conclusion : Alcohol consumption was significantly higher in the indirectly traumatized group. This group also included more members at high risk for PTSD. Further research, with a larger group of indirectly traumatized firefighters and ongoing investigation of PTSD development and other psychiatric symptoms, is needed.

• 실천공학교육논문지
• /
• 제13권2호
• /
• pp.301-304
• /
• 2021

본 연구에서는 코로나-19시대에 개인인식 모듈과 발열감지 모듈이 상호연동을 통해서 동시에 두가지 기능을 수행할 수 있는 모듈을 개발하였다. 이는 기존 시스템에서 발생하는 개인인식 모듈의 호환 문제와 발열감지의 별도 시행에 따르는 정체 시 발생 가능한 2차 감염 문제를 동시에 해결할 수 있다. 따라서, 본 연구에서는 NFC, Bluetooth 메인보드를 개발하였고, 발열 감지를 위해서 array 방식의 비접촉 온도센서를 적용하였다. 개발된 시스템은 AI 자동화 출인통제가 필요한 공공기관이나 민간기업에서 유동인구의 출입관리와 효율적인 방역을 동시에 실현할 수 있을 것으로 기대된다. 또한 개발 시스템의 모듈을 이용한 임베디드 프로그래밍과 웹 프로그래밍 구현방법을 교육 프로그램으로의 연계도 가능할 것으로 판단된다.

• The Journal of Advanced Prosthodontics
• /
• 제11권3호
• /
• pp.147-154
• /
• 2019

PURPOSE. This study aimed to evaluate the effect of two different implant-abutment connection structures with identical implant design on peri-implant bone level. MATERIALS AND METHODS. This clinical study was a patient-blind randomized controlled trial following the CONSORT 2010 checklists. This trial was conducted in 24 patients recruited between March 2013 and July 2015. Implants with internal friction connection were compared to those with external hex connection. One implant for each patient was installed, replacing the second molar. Implant-supported crowns were delivered at four months after implant insertion. Standardized periapical radiographs were taken at prosthesis delivery (baseline), and one year after delivery. On the radiographs, distance from implant shoulder to first bone-to-implant contact (DIB) and peri-implant area were measured, which were the primary and secondary outcome, respectively. RESULTS. Eleven external and eleven internal implants were analyzed. Mean changes of DIB from baseline to 1-year postloading were 0.59 (0.95) mm for the external and 0.01 (0.68) mm for the internal connection. Although no significant differences were found between the two groups, medium effect size was found in DIB between the connections (Cohen's d = 0.67). CONCLUSION. Considering the effect size in DIB, this study suggested the possibility of the internal friction connection structure for more effective preservation of marginal bone.

• Journal of Electrochemical Science and Technology
• /
• 제12권4호
• /
• pp.458-464
• /
• 2021

Lithium ion batteries (LIBs) is a kind of rechargeable secondary battery, developed from lithium battery, lithium ions move between the positive and negative electrodes to realize the charging and discharging of external circuits. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials in which organic imidazole esters are cross-linked to transition metals to form a framework structure. In this article, ZIF-67 is used as a sacrificial template to prepare nano porous carbon (NPC) coated cobalt nanoparticles. The final product Co/NPC composites with complete structure, regular morphology and uniform size were obtained by this method. The conductive network of cobalt and nitrogen doped carbon can shorten the lithium ion transport path and present high conductivity. In addition, amorphous carbon has more pores that can be fully in contact with the electrolyte during charging and discharging. At the same time, it also reduces the volume expansion during the cycle and slows down the rate of capacity attenuation caused by structure collapse. Co/NPC composites first discharge specific capacity up to 3115 mA h/g, under the current density of 200 mA/g, circular 200 reversible capacity as high as 751.1 mA h/g, and the excellent rate and resistance performance. The experimental results show that the Co/NPC composite material improves the electrical conductivity and electrochemical properties of the electrode. The cobalt based ZIF-67 as the precursor has opened the way for the design of highly performance electrodes for energy storage and electrochemical catalysis.

• Smart Structures and Systems
• /
• 제29권2호
• /
• pp.375-387
• /
• 2022

One of the latest teaching strategies is smart classroom teaching. Teaching is carried out with the assistance of smart teaching technologies to improve teacher-student contact, increase students' learning autonomy, and give fresh ideas for the fulfillment of students' deep learning. Computer-based technology has improved students' language learning and significantly motivating them to continue learning while also stimulating their creativity and enthusiasm. However, the difficulties and barriers that many EFL instructors are faced on seeking to integrate information and communication technology (ICT) into their instruction have raised discussions and concerns regarding ICT's real worth in the language classroom. This is a case study that includes observations in the classroom, field notes, interviews, and written materials. In EFL classrooms, both computer-based and non-computer-based activities were recorded and analyzed. The main instrument in this study was a survey questionnaire comprising 43 items, which was used to examine the efficiency of ICT integration in teaching and learning in public schools in Kuala Lumpur. A total of 101 questionnaires were delivered, while each responder being requested to read the statements provided. The total number of respondents for this study was 101 teachers from Kuala Lumpur's public secondary schools. The questionnaire was randomly distributed to respondents with a teaching background. This study indicated the accuracy of utilizing Teaching-Learning-Based Optimization (TLBO) in analyzing the survey results and potential for students to learn English as a foreign language using computers. Also, the usage of foreign language may be improved if real computer-based activities are introduced into the lesson.

• 수산해양기술연구
• /
• 제58권4호
• /
• pp.367-373
• /
• 2022

We analyzed work safety risk factors, which are likely to occur during fishing in gillnet fishing vessels using the written verdict of the Korea Maritime Safety Tribunal from 2016 to 2020, and considered work safety management. Of the total of 37 fatal accidents, three cases in the East Sea, six cases in the South Sea, and 28 cases in the West Sea were very frequent. The accident rate per vessel by sea area (%) was 0.08% in East Sea, 0.12% in South Sea, and 0.40% in the West Sea. Based on the East Sea, the number of fatal accidents was 1.6 times higher in the South Sea and 5.4 times higher in the West Sea. Six cases (16.2%) occurred during departure and preparation for fishing in the fishing process, and all other 31 cases (83.8%) occurred during fishing operation. In the order of accident types, 21 cases (56.8%) of being struck by object, eight cases (21.6%) of contact with machinery and six cases (16.2%) of falls from height were found to be fatal accidents in gillnet fishery. Human factors, such as fishers' carelessness and negligent safety management by captain accounted for 27 cases (73.0%) of the main cause, and 35 cases (94.6%) of the secondary cause. In addition to human factors such as fisher's carelessness and negligent safety management by captain, mechanical factors, environmental factors and management factors must be improved together to reduce human casualties. These results are expected to be utilized as basic data for reducing safety accidents during the work of fishers.

• 근관절건강학회지
• /
• 제30권3호
• /
• pp.242-253
• /
• 2023

Purpose: The purpose of this study was to identify factors associated with physical activity in older adults living alone. Methods: This is cross-sectional, correlational study used secondary data from the 2019 Community Health Survey. The participants were 19,134 older adults aged 65 years or older and living alone. Data were analyzed using descriptive statistics, the 𝜒² test, and linear regression with the SPSS/WIN 27.0 program. Results: The participants' average amount of physical activity was 1,359.32 MET-min/week; 50.7% were inactive, 38.6% were minimally active, and 10.7% were health-promoting active. Demographic factors that predicted physical activity were gender, age, education level and monthly income, whereas health behavior factors included subjective health status and high risk drinking (R²=.055, p<.001). Psychological factors were sleeping time, stress, depression and fear of falling, and social factors included social contact with neighbors or friends, and participation in social or leisure activites(R²=.070, p<.001). Conclusion: It is important to determine the level of physical activity in older adults living alone. Demographic characteristics, health behaviors, psychological factors, and social factors should be considered in the development of specific and integrated nursing interventions to increase physical activity in older adults.

• Annals of Occupational and Environmental Medicine
• /
• 제34권
• /
• pp.13.1-13.11
• /
• 2022

Background: Work is an inseparable element of a person's life, and violence in the workplace has various effects on individual workers and companies. While most studies have focused on specific industries, very few studies have investigated the influence of workplace violence by co-workers. Therefore, this study aimed to evaluate the association between workplace violence and work-related depression/anxiety in various occupations by differentiating the perpetrators of violence as co-workers and clients. Methods: This study was conducted based on data from the 4th and 5th Korean Working Conditions Surveys (KWCS). The experience of workplace violence was classified in terms of the perpetrator: workplace violence by co-workers and that by clients. Work-related depression and anxiety were assessed using questions about health problems related to depression and anxiety and whether the problems were related to work. Descriptive statistics, χ² tests, and multiple logistic regression analyses were performed using the SPSS 26.0. Results: After adjusting for sociodemographic characteristics (age, education, income, subjective health status) and occupational characteristics (occupation, weekly working hours, type of employment, size of workplace, and shift work), male workers with experience of workplace violence by co-workers were found to be at a higher risk of work-related depression/anxiety (odds ratio [OR], 11.52; 95% confidence interval [CI], 8.65-15.36). The same was confirmed for female workers (OR, 10.89; 95% CI, 7.90-15.02). Conclusions: Employees who experienced workplace violence from co-workers were found to be more vulnerable to work-related depression/anxiety. Continuous contact between the victim and the perpetrator may occur, and the possibility of a secondary assault can frighten the victim. Appropriate prevention and intervention measures that focus on the perpetrators of violence are needed.