• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.121-128
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• 2005

Tho existing TCP(Transmission Control Protocol) is known to be unsuitable for a network with the characteristics of high RDP(Bandwidth-Delay Product) because of the fixed small or large buffer size at the TCP sender and receiver. Thus, some trial cases of adjusting the buffer sizes automatically with respect to network condition have been proposed to improve the end-to-end TCP throughput. ATBT(Automatic TCP fluffer Tuning) attempts to assure the buffer size of TCP sender according to its current congestion window size but the ATBT assumes that the buffer size of TCP receiver is maximum value that operating system defines. In DRS(Dynamic Right Sizing), by estimating the TCP arrival data of two times the amount TCP data received previously, the TCP receiver simply reserves the buffer size for the next arrival, accordingly. However, we do not need to reserve exactly two times of buffer size because of the possibility of TCP segment loss. We propose an efficient TCP buffer tuning technique(called TBT-PLR: TCP buffer tuning algorithm based on packet loss ratio) since we adopt the ATBT mechanism and the TBT-PLR mechanism for the TCP sender and the TCP receiver, respectively. For the purpose of testing the actual TCP performance, we implemented our TBT-PLR by modifying the linux kernel version 2.4.18 and evaluated the TCP performance by comparing TBT-PLR with the TCP schemes of the fixed buffer size. As a result, more balanced usage among TCP connections was obtained.

• Korean Journal of Community Nutrition
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• v.23 no.4
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• pp.318-332
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• 2018

Objectives: The purpose of this study was to investigate the behavioral modification of obese adults who underwent nutritional and physical activity education. Twenty obese females, aged 20-60 years old, with BMIs (Body Mass Index) >30 or body fat (%) >40 were subjected to this study. Methods: The physical activity education program consisted of doing exercise in a gymnasium together or home exercise. Dietary attitudes and dietary intakes were assessed using weight control, physical activity, and eating habits. The nutrition-exercise educational period was 12 weeks. Results: After the study period, there was significant improvement in physical activity and eating habits score. Furthermore, there was a significant increase in the dietary intakes of fiber, iron, potassium, vitamin A, vitamin $B_6$, and niacin. Blood pressure, blood glucose, and total cholesterol levels showed a tendency to decrease, but there was no significant difference. BMI, fat mass, abdominal circumference, and visceral fat levels were significantly reduced while muscle mass significantly increased. Conclusions: This study suggests that behavioral modification by nutrition and physical activity education with feedback has positive effects on dietary intake and anthropometric biomarkers in obese adults. Therefore, lifestyle interventions of this kind could be recommended as a method for obesity management.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.16-27
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• 2017

IEEE 802.15.6 standard, a Wireless Body Area Network, aims to transfer not only medical data but also non-medical data, such as physical activity, streaming, multimedia game, living information, and entertainment. Services which transfer those data have very various data rates, intervals and frequencies of continuous access to a medium. Therefore, an efficient anti-collision operations and medium assigning operation have to be carried out when multiple nodes with different data rates are accessing shared medium. IEEE 802.15.6 standard for CSMA/CA medium access control method distributes access to the shared medium, transmits a control packet to avoid collision and checks status of the channel. This method is energy inefficient and causes overhead. These disadvantages conflict with the low power, low cost calculation requirement of wireless body area network, shall minimize such overhead for efficient wireless body area network operations. Therefore, in this paper, we propose a medium access scheduling scheme, which adjusts the time interval for accessing to the shared transmission medium according to the amount of data for generating respective sensor node, and a priority control algorithm, which temporarily adjusts the priority of the sensor node that causes transmission concession due to the data priority until next successful transmission to ensure fairness.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1770-1780
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• 1997

Our problem is improvement of image quality because it is inevitable cell loss of image data when traffic congestion occurs. If cells are discarded indiscriminately in transmission of MPEG video data, it occurs severe degradation in quality of service(QOS). In this paper, to solve this problem, we propose two method. The first, we analyze the traffic characteristics of an MPEG encoder and generate high priority and low priority data stream. During network congestion, only the least low priority cells are dropped, and this ensures that the high priority cells are successfully transmitted, which, in turn, guarantees satisfactory QoS. In this case, the prioritization scheme for the encoder assigns components of the data stream to each priority level based on the value of a parameter ${\beta}$. The second, Number of high priority cells are increased when value of ${\beta}$ is large. It occurs the loss of high priority cell in the congestion. To prevent it, this paper is regulated to data stream rate as buffer occupancy with UPC controller. Therefore, encoder's bandwidth can be calculated renegotiation of the encoder and networks. In this paper, the encoder's bandwidth requirements are characterized by a usage parameter control (UPC) set consisting of peak rate, burstness, and sustained rate. An adaptive encoder rate control algorithm at the Networks Interface Card(NIC) computes the necessary UPC parameter to maintain the user specified quality of service. Simulation results are given for a rate-controlled VBR video encoder operating through an ATM network interface which supports dynamic UPC. These results show that dynamic bandwidth renegotiation of prioritized data stream could provided bandwidth saving and significant quality gains which guarantee high priority data stream.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.161-170
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• 2023

This study aims to verify the relationship between employer's perception of employment for the disabled and employment satisfaction, and the mediating effect of perception of employment assistance for the disabled and the moderating effect of education and training support. For the purpose of this study, 4,332 companies were reorganized among the data of the 2021 Survey on Employment of Persons with Disabilities conducted by the Korea Employment Agency for the Disabled. Data analysis used SPSS 23.0 and AMOS 23.0, and structural equation model analysis was performed to understand the relationship between variables. As a result of the study, there was a significant influence between employer's perception of employment for the disabled and employment satisfaction, and the partial mediating effect of employment company contribution was confirmed. In addition, it was found that there was a moderating effect according to the presence or absence of education and training support. Through the results of this study, it is significant that factors that can affect environmental composition were considered in various ways to increase the employment rate of the disabled, and based on these results, implications for increasing the employment rate of the disabled were presented.

• Korean Journal of Social Welfare Studies
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• v.42 no.4
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• pp.217-238
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• 2011

This study aims to investigate the effects of active coping of spouses on recidivism of domestic violence. In order to obtain better study results, 21-month follow up interview was conducted for spouses of batterers who completed domestic violence batterer intervention program. Spouses were interviewed for three times; 9-month, 15-month, and 21-month after program completion. Finally, data till 15-month follow-up was used to manage sample size problem. As a results, a total number of 76 spouses were included for final analysis. Data was collected from 2008 to 2009. Based on sample size and study objects, PLS(Partial Least Square) analysis was used. the prevalence rates of emotional abuse was 77.6% at the first interview but 41.3% at the second interview. For physical violence each rate were 43.1% and 18.4%. For emotional violence, problem-solving strategy among active coping shows significant moderating effects on reducing emotional violence(p<.001) while help-seeking among active coping has significant effects on decrease physical violence(p<.01).

• Journal of Korean Home Economics Education Association
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• v.18 no.3 s.41
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• pp.23-40
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• 2006

The purpose of this study was to examine co-ed high school students' concern for appearance, weight control attitude and food behavior. The subjects were 405 students(boys 197, girls 208) in Sokcho area. Most of the students had much interest in appearance, and their perception of body type was significant differences between boys and girls(p<,00l). 22.8% of boys expressed satisfaction at their own body type. while just 9,6% of the girls were contented with their body type. In interest toward weight control. 43.7% of the boys and 79.8% of the girls had a regard for weight control. In relationship between weight control interest and the body type perception, there were significant differences among group of caring about weight control. moderate group and indifferent group(p<,00l), regardless of gender. As a whole, 41.3% of group that cared about weight control found themselves a little fat. Most of the boys who considered themselves thin(24,4%) were much concerned about weight control. where as girls who thought of themselves as thin were little interested in. Body type satisfaction was significant differences among interested group, moderate group and indifferent group(p<.00l). It appeared that they had breakfast very irregularly, But 86.9% of the total students had dinner, which indicated dinner was taken relatively on a regular basis. Among three meals, dinner was skipped the least, 23,5% (17.8% of the boys and 28,9% of the girls) went without breakfast everyday. For the reason, 65.1% of the overall students didn't eat breakfast due to time constraints, and lunch(39.8%) and dinner(31.3%) were skipped largely because eating them was troublesome. Less students went without meals to lose weight. and lunch(7.0%) was skipped more than breakfast(1.3%), and dinner(13,8%) was skipped more than lunch, This study suggested that nutrition education for high school students should be planned to provide nutrition information regarding desirable weight control as well as modifying diets and food behaviors.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.2
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• pp.227-231
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• 2010

The TFRC is a congestion control mechanism which supports the requirements of video streaming applications and controls its sending rate by using the information such as loss event rate and RTT (round-trip time). However, TFRC has a performance degradation in wireless networks because it performs congestion control by judging all the losses occurred in wireless network as a congestion signal. In this paper, we propose new loss discrimination mechanism which is using ECN in order to solve the performance degradation of TFRC. Through the results of simulation, we proved that the proposed mechanism can improve the performance of TFRC.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.06a
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• pp.54-54
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• 2001

End hall type 이온건을 이용하여 다층 다이아몬드상 차본(DLC) 필름을 M2 steel 기판 위에 합성하였다. 다충 다이아몬드상 카본 필름은 순수 DLC 필름과 실라콘 함유 D DLC 필름의 조합으로 구성되어 있으며, $C_6H_6$ 및 수소 희석된 30% 를 사용하여 증착 하였다. 생성된 DLC 박막의 조성은 $C_6H_6$과 $SiH_4$ 가스의 비를 조절함으로써 변화시켰으며, 250 kHz의 고주파 전원을 바이어스 전원으로 사용하여 박막의 물성을 변화시켰다. DLC 박막의 두께와 다층의 구조 및 종류(2충, 4충)는 코팅 공정의 실험 변수로서 변화시켰다. 직경 3 mm의 루비볼을 사용하여 ball-on-disk 방식으로 마모 시험을 행하였으며, 하중은 490 g, 500 rpm에서 상대습도를 5 % 이하와 80 % 이상으로 변화시켜가며 시행하였다. 100,000 cycle 회전 후 측정된 시편의 마모상태는 5 % 이하의 습 도에서 4층 구조의 박막이 2충 구조의 박막보다 2배 이상 낮은 마모률을 보였으며 그 값은 각각 $2~3{\times}\;10^{-8}\;\textrm{mm}^3/rev$와 $1~2{\times}\;10^{-7}\;\textrm{mm}^3/rev$로 나타내었다. 80% 이상의 습도에서도 마모률의 변화는 저습에서의 경우와 유사하였다. 또한 Si함유 DLC 다층 박막이 저습 및 고습에서 더욱 안정한 마찰 마모 거동을 보였다.

• KOREAN POULTRY JOURNAL
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• v.41 no.6
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• pp.116-119
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• 2009

매년 발생하는 닭 질병은 일정한 발생동향을 나타낸다. 이러한 질병 발생동향에 영향을 미치는 요인들은 그 변화에 따라 질병발생의 패턴이 바뀌게 된다. 질병 발생에 영향을 주는 요인들로는 기후, 유행하는 병원체, 면역상태, 백신, 주령, 복합감염 등 매우 다양하다. 이외에도 수없이 많은 요인들이 있으며, '새로운 백신의 적용'과 같은 비교적 단시간에 걸쳐 질병 발생동향을 결정짓는 요인도 있다. 어느해보다도 지난 $6{\sim}7$개월간의 질병 발생률은 현저히 줄어들었다. 그렇다면 '어떤 요인의 변화가 질병 발생률이 줄어들 수 있게 작용하였을까?'하는 의문을 가져보는 것도 의미가 있을 것으로 보인다. 질병 발생에 영향을 주는 요인들이 모두 인위적으로 조절할 수 있는 것은 아니다. 그러나 질병 발생을 줄일 수 있는 요소들이 계획된 인위적인 것들이었다면 그를 더 강화하거나 다른 질병에 대해서도 적용방법을 모색할 수 있는 동기가 될 것이다. 굳이 6월 '현장질병가이드'에서 질병발생 동향을 분석하게 된 이유는 지난 몇 년간의 일정한 질병발생 동향이 지난 $6{\sim}7$개월 사이에 많은 변화를 보여주었기 때문이다. 질병발생은 경제적인 면에서 개인농가 뿐만 아니라 국가적으로도 상당한 피해를 입힌다. 질병 발생동향에 좋은 영향으로 작용된 요인들과 그렇지 못한 것들에 대해 면밀히 분석하여 이에 대비하다보면 농가에 큰 도움이 될 것으로 생각된다. 물론 보는 관점에 따라 분석에 대한 결과가 다르게 나타날 수도 있다고 생각되지만 제시될 분석요인들에 대해서 함께 생각해보는 좋은 기회가 되기를 바란다.