• Investigative Magnetic Resonance Imaging
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• 제21권2호
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• pp.102-105
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• 2017

In adolescents, sleep deprivation problem is getting worse, and increased caffeine consumption is considered to relieve the stress caused by sleep deprivation and academic burden. In this study, immediate neurologic effects of caffeine intake on adolescents were evaluated in three high school students using the ${\gamma}-aminobutyric$ acid (GABA)/creatine ratio on magnetic resonance spectroscopy (MRS). MEGA-PRESS MRS and TE 135 ms single voxel MRS were performed in the anterior cingulate cortex before and after drinking a cup of coffee, which contained 104 mg of caffeine. GABA and creatine were measured on LCModel 6.3, respectively. In all three students, GABA/creatine ratios were decreased after caffeine intake. The GABA/creatine ratios obtained before caffeine intake were decreased after caffeine intake in all the three adolescents. In this preliminary study, caffeine intake caused an immediate decrease in the GABA/creatine ratio in the brain and it may be related to the neurologic effects of caffeine on an adolescent's brain.

• Journal of Communications and Networks
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• 제18권4호
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• pp.619-628
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• 2016

This paper describes a theoretical framework for rate allocation to maximize the power efficiency of overall heterogeneous wireless networks whose users are assumed to have multihoming capabilities. Therefore, the paper first presents a power consumption model considering the circuit power and radio transmission power of each wireless network. Using this model, two novel power efficient rate allocation schemes (PERAS) for multihoming services are proposed. In this paper, the convex optimization problem for maximizing the power efficiency over wireless networks is formulated and solved while guaranteeing the required quality of service (QoS). Here, both constant bit rate and variable bit rate services are considered. Furthermore, we extend our theoretical framework by considering the sleep-operation management of wireless networks. The performance results obtained from numerical analysis reveal that the two proposed schemes offer superior performance over the existing rate allocation schemes for multihoming services and guarantee the required QoS.

• 한국학교보건학회지
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• 제32권1호
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• pp.1-9
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• 2019

Purpose: The purpose of this study was to identify the prevalence, subtypes and risk factors of Irritable Bowel Syndrome (IBS) among male adolescents. Methods: The survey was conducted on male adolescents (n=441) attending a high school. Rome IV criteria was used to diagnose IBS. Data on health promoting behaviors, psychological distress, sleep hygiene practices were collected using self-administered structured questionnaires. Results: The prevalence of IBS was 11.1% and the subtypes were mixed (77.5%), unclassified (10.2%), diarrhea-predominant (8.2%), and constipation-predominant (4.1%). Risk factors influencing IBS were sleeping time (Odds Ratio [OR]=1.00, 95% Confidence Interval [CI]: 0.99~1.00), anxiety, a subfactor under psychological distress (OR=1.12, 95% CI: 1.02~1.22), and arousal-related behaviors, a subfactor under sleep hygiene practices (OR=1.10, 95% CI: 1.03~1.17). Conclusion: Our findings indicated that IBS is a common problem in male adolescents. It is necessary to develop school-based intervention strategies addressing sleeping time, anxiety and arousal-related behaviors in order to prevent and improve IBS in male adolescents.

• 한국통신학회논문지
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• 제38B권8호
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• pp.623-631
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• 2013

무선랜 인터페이스는 스마트폰, 태블릿과 같은 모바일 단말의 배터리를 급격히 소비하는 주된 요인 중의 하나이다. 이에, 대부분의 상용 모바일 단말은 네트워크 트래픽이 없을 때에 무선랜 인터페이스를 SLEEP 상태를 유지하여 배터리를 절약하는 power saving 기법을 사용하고 있다. 하지만 Access Point (AP)는 단순히 서버로부터 수신한 데이터 패킷을 해당 모바일 단말 측으로 즉시 전송하려 하기 때문에, 경우에 따라 모바일 단말이 항상 AWAKE 상태를 유지하여 배터리가 급격하게 소모되는 문제를 일으킬 수 있다. 본 논문에서는 이러한 문제를 지적하고, AP의 적응적 패킷 스케줄링 기법을 통해 모바일 단말의 배터리를 절약할 수 있는 새로운 기법을 제안한다. 또한 테스트 베드 기반의 실험 결과로부터 제안된 기법이 기존 기법보다 power saving 성능을 50%이상 향상시킴을 확인하였다.

• 기본간호학회지
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• 제9권2호
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• pp.180-189
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• 2002

Purpose : This study focused on affirming of the effects of Dan-jun breathing exercise experienced by women in midlife. Method: The data were collected via direct interview from 20 participants, who participated in a Dan-Jun exercise program during three months. Collected data were analyzed by content analysis. Result : 1. As for the health problems of women in midlife before the Dan-jun exercise program, 93 items were extracted in the content analysis These items were categorized into 59 attributes and 15 higher attributes. 1) Of the 59 attributes of health problems, shoulder pain (30%) was the most dominant. 2) The 15 higher attributes consisted for the physical domain of, weakness, pain, joint stiffness, sexual problem, sleep disorder, gastro-intestinal disorder. menstrual irregularity. circulatory disorder, respiratory disorder. constipation, urinary incontinence, and for the psychological domain, anger, emptiness, depression, and anxiety. 2. As for the effects experienced by women in midlife after the Dan-jun exercise program, 169 items were extracted in the content analysis. These items were categorized into 85 attributes and 14 higher attributes. 1) Of 85 attributes, lightening of physical condition (55%) was the most dominant. 2) The higher attributes consisted in physical domain of, recovery of vigor, pain relief, menstrual regularity and improvements in flexibility. sexual problem, sleep disorder, gastro-intestinal disorder, circulatory disorder constipation, respiratory disorder and urinary incontinence, and for the psychological domain, relaxation, cultured mind and self-confidence. Conclusions : Dan-jun breathing exercise program for three months showed positive effects on physical and psychological health in women in midlife. In this context, it can be also considered as a significant nursing intervention for maintenance and promotion of the health of these women.

• Management Science and Financial Engineering
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• 제17권2호
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• pp.39-62
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• 2011

In wireless sensor network, since each sensor is equipped with a limited power, efficient use of the energy is important. One possible network management scheme is to cluster the sensors into several sets, so that the sensors in each of the sets can completely perform the monitoring task. Then the sensors in one set become active to perform the monitoring task and the rest of the sensors switch to a sleep state to save energy. Therefore, we rotate the roles of the active set among the sensors to maximize the network lifetime. In this paper, we suggest an optimal algorithm for the maximum lifetime coverage problem which maximizes the network lifetime. For comparison, we implemented both the heuristic proposed earlier and our algorithm, and executed computational experiments. Our algorithm outperformed the heuristic concerning the obtained network lifetimes, and it found the solutions in a reasonable amount of time.

• 한국항공운항학회지
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• 제27권3호
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• pp.106-111
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• 2019

Pilot has been fighting to get over fatigue during flight and thought it as a hinderance for safe flight. The fatigue related problem has been the biggest obstacle for aviation safety so far. Even though pilots and airlines try their best to overcome fatigue during flight, they couldn't overcome this problem. So the airliners let the pilot sleep during flight if pilots are too tired with the report. It is controlled rest used and managed by several European airliners. So this study tries to get Korean airline pilots' fatigue information and figure out the cause and reduce it.

• 한국간호교육학회지
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• 제13권2호
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• pp.257-265
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• 2007

Purpose: This study was done to investigate sexual problem behaviors of high school students in one province, North Cholla. Method: The participants in this research were 951 high school students, grades 1, 2 and 3, chosen at random in big cities, small towns and rural areas of North Cholla Province. Result: The routes for sexual knowledge acquisition were through a peer group or an older member(35.8%), internet(29.8%), classes and the teacher at school(18.8%), multimedia(8.4%) and parents (7.2%). The percentages for domains of sexual problem behaviors were masturbation 36.7%, sexual impulse 35.6%, voyeurism 12.6%, sexual violence 9.6%, transvestism 4.1%, prostitution 3.5%, exhibitionism 3.1%, and pregnancy of a female student 0.6%. Sexual problem behaviors experienced by 30% or more of the students were reported as the experience of the desire to embrace, the desire to kiss, the desire to touch a friend's body of the opposite sex, masturbation and the desire to sleep with a friend of the opposite sex. The biggest sexual problem behaviors for the students were sexual impulses toward friends of the opposite sex and masturbation. These experience rates were higher for boys than for girls(p<.05), higher vocationally than academicly(p<.05), and higher in the largest cities than smaller cities and rural area(p<.05). Conclusion: These findings suggest that systematic programs that focus on a problem solution method should be developed for sexual problem behavior prevention.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.684-702
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• 2011

This paper proposes a TDMA-based multichannel medium access control (MAC) protocol for QoS provisioning in mobile ad hoc networks (MANETs) that enables nodes to transmit their packets in distributed channels. The IEEE 802.11 standard supports multichannel operation at the physical (PHY) layer but its MAC protocol is designed only for a single channel. The single channel MAC protocol does not work well in multichannel environment because of the multichannel hidden terminal problem. Our proposed protocol enables nodes to utilize multiple channels by switching channels dynamically, thus increasing network throughput. Although each node of this protocol is equipped with only a single transceiver but it solves the multichannel hidden terminal problem using temporal synchronization. The proposed energy efficient multichannel MAC (EM-MAC) protocol takes the advantage of both multiple channels and TDMA, and achieves aggressive power savings by allowing nodes that are not involved in communications to go into power saving "sleep mode". We consider the problem of providing QoS guarantee to nodes as well as to maintain the most efficient use of scarce bandwidth resources. Our scheme improves network throughput and lifetime significantly, especially when the network is highly congested. The simulation results show that our proposed scheme successfully exploits multiple channels and significantly improves network performance by providing QoS guarantee in MANETs.

• 대한간호학회지
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• 제26권4호
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• pp.930-945
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• 1996

The purpose of this study was to identify the degree to which nursing diagnoses accepted by NANDA are used and to identify problems in application of nursing diagnoses in clinical practice. With the expanding potential for computerization of nursing diagnosis, the survey also included data on the present status of hospital computerization and willingness to use computerized nursing diagnoses. The data collection was done from July 1 to August 3, 1996 using structured questionnaires. The questionnaires were mailed to 1,126 head nurses working in 44 hospitals with on occupacy of over 500 beds located in Korea, of these, 883 were returned from 40 hospitals. Among the 883 questionnaires, 867 were used for the analysis. The results of the analysis are as follows 1. Among 109 nursing diagnoses, pain, constipation, diarrhea, hyperthermia, high risk for infection, sleep pattern disturbance, and anxiety, chronic pain, altered urinary elimination, and altered nutrition : less than body requirements were the ten most frequently used diagnoses. 2. The primary problem in the use of nursing diagnoses was lack of time and personnel. Others were lack of knowledge and motivation, absence of protocols and absence of the appropriate methods to apply nursing diagnoses. 3. Among the 40 hospitals, 27 hospitals used a computerized system and expressed willingness to utilize the computerized system of nursing diagnoses that is planned for the future.