• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.33-43
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• 2010

Recently, users want to use real-time multimedia services, such as internet, VoIP, etc., using their IEEE 802.11 wireless lan mobile stations. In order to provide such services, a handoff among access points is essential to support the mobility of a node, in such an wide area. However, the legacy handoff methods of IEEE 802.11 technology are easy to lose connections. Also, the recognition of a disconnection and channel re-searching time make the major delay of the next AP to connect. In addition, because IEEE 802.11 decides the selection of an AP depending only on received signal strength, regardless of a node direction, position, etc., it cannot guarantee a stable bandwidth for communication. Therefore, in order to provide a real-time multimedia service, a node must reduce the disconnection time and needs an appropriate algorithm to support a sufficient communication bandwidth. In this paper, we suggest an algorithm which predicts a handoff point of a moving node by using GPS location information, and guarantees a high transmission bandwidth according to the signal strength and the distance. We implemented the suggested algorithm, and confirmed the superiority of our algorithm by reducing around 3.7ms of the layer-2 disconnection time, and guaranteed 24.8% of the communication bandwidth.

• The Transactions of the Korea Information Processing Society
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• v.2 no.6
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• pp.985-994
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• 1995

In this paper, we propose two hot standby architectures which not only provide high system availability but also lose little data on fault occurrence. In order to evaluate the performance of the proposed hot standby architectures, the warm standby architecture. In order to evaluate the performance of the propose d hot standby architectures, the warm standby architecture which is made from the hot standby architecture by eliminating its synchronization unit is considered. After system unavailability for each architecture is computed by using the corresponding Markov state diagram, the results are compared and evaluated. As the results, in most cases, hot standby architectures have higher availability than warm standby architecture. Also, hot standby architecture with external synchronization unit always maintains a little higher availability than hot standby architecture with internal synchronization unit. Active set time and personnel recovery rate for each architecture have little effect on system availability. However, in the case that data recovery time is too long, system availabilities of hot standby architectures and warm standby architecture degrade rapidly. In this case, the performance degradation of hot standby architectures is severe, and system availabilities of hot standby architectures eventually become lower than system availability of warm standby architecture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.635-644
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• 2009

Image processing technique in the outdoor environment is very sensitive, and it tends to lose a lot of accuracy when it rapidly changes by outdoor environment. Therefore, in order to calculate accurate traffic information using the traffic monitoring system, we must resolve removing shadow in transition time, Distortion by the vehicle headlights at night, noise of rain, snow, and fog, and occlusion. In the research, we developed a system to calibrate the amount of traffic, speed, and time occupancy by using image processing technique in a variety of outdoor environments change. This system were tested under outdoor environments at the Gonjiam test site, which is managed by Korea Institute of Construction Technology (www.kict.re.kr) for testing performance. We evaluated the performance of traffic information, volume counts, speed, and occupancy time, with 4 lanes (2 lanes are upstream and the rests are downstream) from the 16th to 18th December, 2008. The evaluation method performed as based on the standard data is a radar detection compared to calculated data using image processing technique. The System evaluation results showed that the amount of traffic, speed, and time occupancy in period (day, night, sunrise, sunset) are approximately 92-97% accuracy when these data compared to the standard data.

• Journal of Community Nutrition
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• v.1 no.1
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• pp.25-32
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• 1999

In this study, focus group interviews were used to investigate female university students' eating behavior, factors related to eating behavior, information sources for nutrition, and formats for nutrition education. Thirty-six students participated in one of five focus groups during December 1998 in Seoul. Focus group discussions were video, audio-taped, transcribed and analyzed by major themes. Results showed that subjects have undesirable eating behaviors, such s eating irregular meals and skipping meals. These behaviors are caused by a lack of time, habit, or for the purpose of losing weight. The students tended to have unbalanced diets and frequently ate out. They had a large amount for dinner and frequently snaked when stressed or had an empty stomach. Most of them were interested in weight control and had attempted to lose weight, but they did not participate in regular exercise. The most frequently used source for nutrition information was the mass media, but much nutrition information was based on what they learned from home economics class during middle to high school. They received more support from mothers, elder sisters, and friends for eating behaviors, such s lowering caloric intake and losing weight. In nutrition education, they wanted to learns behaviorla skills to adopt healthy behaviors, including meal planning, applying scientific weight control methods, exercise that fit into their lives, and stress management. They also mentioned that nutrition screening and assessment should be a part of nutrition education programs. As a method for nutrition education, subjects preferred an individualized approach to group education. These results provide the qualitative information for developing nutrition education programs which will be implemented for Korean University students.

• Asian Oncology Nursing
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• v.1 no.1
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• pp.18-31
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• 2001

This Research was designed to develop an instrument that can be used for measuring and analysing the degree of the quality of life of the Allogenic bone marrow transplantation survivors and to provide basic data to help them attain a better quality of life. The subjects of this study were a total of 101 people who were undergone Allogenic bone marrow transplantation and were over 100 days after transplantation. Data were collected during the period from September 3 to December 2. 2000. In Developing this instrument, the researcher established a conceptual framework based on the result of previous research, interview of patients and medical staff and researcher's experience. The scale for this instrument consisted of 51 items. Responses were obtained from the respondents through a self reporting method and each item had a possible score of 5. The collected data were analyzed using the SPSS program. The reliability of the scale was tested by Cronbach‘s alpha. For the examination of the component factors of the measuring instruments, factor analysis method was used. Examination of the difference in the quality of life as related to demographic variables was done using t-test, analysis of variance(ANOVA). For the examination of the major variables influencing the quality of life, Pearson's Correlations was used. The results were as follows: (1) The reliability of the instrument was 0.90 (Cronbach's alpha) (2) The validity of the instrument was tested by factor analysis. The result of the factor analysis of the 51 items is making up the instruments were classified into the following factor; emotional state, Interpersonal problem, physical problem, spiritual state, social problem, decrease of physical energy, physical problem-eye, physical problem-skin and mucosa, health awareness, elimination problem, worry about health, financial problem, sexual problem. (3) Demographic variables related to quality of life is the time after transplantation. GVHD experience, lose of job. Age at the transplantation, diagnosis, type of the transplantation, marital status, monthly income, educational background, sex, religion are not related to the quality of life.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.272-281
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• 2013

Concrete filled tube (CFT) columns, which consist of a steel tube filled with concrete, combine the benefits of the two materials. The steel tube provides a confining pressure to the concrete, while the local buckling of steel plate can be prevented by the concrete core. CFT columns also have a high fire resistance due to the heat storage effect of concrete under fire. For this reason, it is possible to develop CFT columns without fire protection measures. CFT columns without fire protection have many advantages, including quality control, cost reduction, better space efficiency and a shorter construction period. Due to these advantages, studies on the development of CFT columns without fire protection measures have been performed. However, CFT columns lose their bearing capacity under fire because the steel tube is exposed to the outside. As a result, the structure is collapsed, causing significant damage. In this research, we made a CFT column using high strength concrete (100 MPa) and high strength steel (800 MPa). We use steel fiber and nylon fiber with concrete to provide fire resistance. We perform the fresh concrete experiment and investigate the fire resistance of the CFT column (${\Box}400{\times}400{\times}15{\times}3000mm$) under loading. To investigate the effect of steel fiber on increasing fire resistance, we compare the fire resistance time according to the steel fiber. Through the test, it was found that the CFT specimen with steel fiber had better fire resistance performance than other cases.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.13-21
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• 2012

The main purpose of this study is to find out how perceived risk elements influence to customer's perceived value and repurchase intention in the electronic commerce environment. To achieve the goal, we set 6 sub-dimension - privacy risk, social risk, time lose risk, economic risk, psychological risk, and performance risk - based on comprehensive consideration of related studies, and established a research model included 2 factors such as perceived value and repurchase intention to measure performance in internet shopping malls. From 174 customers of the electronic commerce shopping malls survey data have been collected and analyzed based on the covariance structural model method. Firstly, four perceived risk characteristics of privacy risk, economic risk, psychological risk, and performance risk are significant effect on perceived value. Secondly, perceived value is very significantly related to repurchase intention in electronic commerce shopping malls. Consequently, we discussed the strategies to create perceived value and repurchase intention in electronic commerce environment. Also, we suggested the implications and further research directions.

• Archives of design research
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• v.19 no.1 s.63
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• pp.129-140
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• 2006

In this study, I would like to suggest a new model of web navigation design which can enhance old-aged users web usability. I would like to prove that when users enjoy web navigation design, older-users access information much more effectively. Using a survey, suggest some types of web navigation designed for old-aged users. After that, based on the result of the prepatory survey, I conducted an experiment with 4 types of web navigation designs, which have been developed to reflect varying stages of comprehensibility. My survey focused three points. First I tested whether they lost their way while searching for information. Secondly, if they did lose their way, I checked whether they could recover from their errors and find their way back. Thirdly, I investigated whether layout, location and size of the web navigation design factors affected usability. The results of my survey indicated that old-aged users spend the shortest time, have the easiest interface, and have least error incidence under the web navigation design to enhance old-aged users web usability.Thus, developing a web navigation design for old-aged users can encourage older people to be more involved with the internet, especially in the aging society.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.1
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• pp.42-51
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• 2008

We believe that smart spaces, offering pervasive services, will proliferate. However, at present, those islands of smart spaces should be joined seamlessly with each other. As users move about, they will have to roam from one autonomous smart space to another. When they move into the new island of smart space, they should setup their devices and service manually or not have access to the services available in their home spaces. Sometimes, there will conflicts between users when they try to occupy the same space or use a specific device at the same time. It will also be critical to elder people who suffer from Alzheimer or other cognitive impairments when they travel from their smart space to other visited spaces (e.g., grocery stores, museums). Furthermore our experience in building the Gator Tech Smart House reveals to us that home residents generally do not want to lose or be denied all the features or services they have come to expect simply because they move to a new smart space. The seamless inter-space interaction requirements and issues are raised automatically when the ubiquitous pervasive computing system tries to establish the user's service environment by allocating relevant resources after the user moves to a new location where there are no prior settings for the new environment. In this paper, we raise and present several critical inter-space interactions issues impacting middleware architecture design of ubiquitous pervasive computing. We propose requirements for resolving these issues on seamless inter-space operation. We also illustrate our approach and ideas via a service scenario moving around two smart spaces.

• Fashion & Textile Research Journal
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• v.21 no.6
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• pp.697-707
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• 2019

This review paper deals with materials, classification, and a current article investigation on smart textile sensors for wearable vital signs monitoring (WVSM). Smart textile sensors can lose electrical conductivity during vital signs monitoring when applying them to clothing. Because they should have to endure severe conditions (bending, folding, and distortion) when wearing. Imparting electrical conductivity for application is a critical consideration when manufacturing smart textile sensors. Smart textile sensors fabricate by utilizing electro-conductive materials such as metals, allotrope of carbon, and intrinsically conductive polymers (ICPs). It classifies as performance level, fabric structure, intrinsic/extrinsic modification, and sensing mechanism. The classification of smart textile sensors by sensing mechanism includes pressure/force sensors, strain sensors, electrodes, optical sensors, biosensors, and temperature/humidity sensors. In the previous study, pressure/force sensors perform well despite the small capacitance changes of 1-2 pF. Strain sensors work reliably at 1 ㏀/cm or lower. Electrodes require an electrical resistance of less than 10 Ω/cm. Optical sensors using plastic optical fibers (POF) coupled with light sources need light in-coupling efficiency values that are over 40%. Biosensors can quantify by wicking rate and/or colorimetry as the reactivity between the bioreceptor and transducer. Temperature/humidity sensors require actuating triggers that show the flap opening of shape memory polymer or with a color-changing time of thermochromic pigment lower than 17 seconds.