• Polymer(Korea)
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• v.24 no.6
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• pp.837-844
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• 2000

The cure behavior of commercial epoxy molding compounds (EMC) commonly used for IC package was studied at constant cure temperatures as well as at constant heating rates using differential scanning calorimetry (DSC), rheometer, and dielectric analyzer (DEA). The cure kinetics were obtained using autocatalytic reaction model according to the Ryan Dutta method after assuming m+n equal to 2. The prediction of reaction rates by the model equation corresponded well to experimental data at all temperatures except for 10$0^{\circ}C$. The phase transitions such as gelation and vitrification occurred during network formation. At each isothermal cure temperature, $T_{g}$ was measured in accordance with cure time, and the vitrification point was attained when $T_{g}$ was equal to $T_{cure}$. The temperature dependence of gel points and vitrification points showed good agreement with Arrhenius relation. DEA using parallel plate electrode was effective for the monitoring of EMC cure. we knew that if the resin systems are materials of comparable quality, $_{gel}$$T_{g}$ is constant regardless of accelerator concentration in TTT (Time-Temperature-Transformation) diagram.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.249-254
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• 2004

The hydro-acoustic method is widely used for estimating biomass and distribution of fisheries resources along the coast and in the ocean. High costs and time are necessary to construct systems for this method and to initially educate specialists. It has been used in fisheries of advanced nations like Japan and Norway, because it is more efficient than other methods. In order to research the behavior of fish around an artificial reef using an echo sounder, volume backscattering strength (SV) and fish per cubic meter (FPCM) of darkbanded rockfish around the model artificial reef in a water tank were measured. Moreover, behavior of fish was observed in an adjacent artificial reef, which was constructed at Tongyeong marine ranching area. Following that, an acoustics survey was conducted at Mirukdo around the Tongyeong marine ranching area, in order to understand the spatial distribution and strength of fisheries resources. Very high patches of fish were found in a wide area around the artificial reef. It is thought that an approaching fish school around the artificial reef can be measured accurately by using an echo sounder of high resolution. Moreover, use of other monitoring methods like of diving or ROV simultaneous with an echo sounder is required in order to grasp the species and ecology of fish inhabiting the area around the artificial reef.

• Journal of Energy Engineering
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• v.21 no.2
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• pp.144-151
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• 2012

A district heating system produces thermal energy and supplies it to a large region. District heating systems can provide higher efficiencies and better pollution control than localized boilers. The heat generated by a district heating system is distributed to the customer via a network of insulated pipes. For the optimal operation of a district heating system, it is important to predict the distributions of pressure, flow rate and temperature of heating fluid within the network of pipes at various operating conditions. In this work, a mathematical modeling was performed to predict the dynamic hydraulic-thermal behaviors of heating fluid in the network of pipes for a district heating system. The mathematical model accounts for the conservations of mass, momentum and energy. In order to verify the validity of modeling, the modeling results were compared with the monitoring data of Gang-nam Branch of District Heating.

• Journal of Preventive Medicine and Public Health
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• v.43 no.5
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• pp.396-402
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• 2010

Objectives: Self-reported anthropometric values, such as height and weight, are used to calculate body mass index (BMI) and assess the prevalence of obesity among adolescents. The aim of this study was to evaluate the validity of selfreported height, weight, and BMI of the Korea Youth Risk Behavior Web-based Survey questionnaire. Methods: A convenience sample of 137 middle school students and 242 high school students completed a selfadministered questionnaire in 2008. Body height and weight were directly measured after self-reported values were obtained from the questionnaire survey. Sensitivity, specificity, and kappa statistics were computed in order to evaluate the validity of the prevalence of obesity (BMI $\geq$ 95th percentile or $\geq$ $25;kg/$m^2$) based on self-reported data. Results: Self-reported weight and BMI tended to be underestimated. Self-reported height tended to be overestimated among middle school females and high school males. Obese adolescents tended to underestimate their weight and BMI and overestimate their height more than non-obese adolescents. The prevalence estimate of obesity based on selfreported data (10.6%) was lower than that based on directly measured data (15.3%). The estimated sensitivity of obesity based on self-reported data was 69.0% and the specificity was 100.0%. The value of kappa was 0.79 (95% confidence interval, 0.70 - 0.88). Conclusions: This study demonstrated that self-reported height and weight may lead to the underestimation of BMI and consequently the prevalence of obesity. These biases should be taken into account when self-reported data are used for monitoring the prevalence and trends of obesity among adolescents nationwide.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.47-54
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• 2020

Developmental disorders are impairments of brain and/or central nervous system and refer to a disorder of brain function that affects languages, communication skills, perception, sociality and so on. In diagnosis of developmental disorders, behavioral response such as expressing emotions in proper situation is one of observable indicators that tells whether or not individual has the disorders. However, diagnosis by observation can allow subjective evaluation that leads erroneous conclusion. This research presents the technological environment and data acquisition system for AI based screening of autism disorder. The environment was built considering activities for two screening protocols, namely Autism Diagnostic Observation Schedule (ADOS) and Behavior Development Screening for Toddler (BeDevel). The activities between therapist and baby during the screening are fully recorded. The proposed software in this research was designed to support recording, monitoring and data tagging for learning AI algorithms.

• Journal of Convergence for Information Technology
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• v.10 no.2
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• pp.21-31
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• 2020

This study tested the effectiveness of commercialized smartphone apps in improving walking activities among college students. 66 participants were randomized into each of four groups that was used different behavior change strategies: monetary rewards app, goal setting and feedback app, gaming app, and self-monitoring control group. 45 participants who completed the experimentation was included in data analysis. Repeated measures ANOVA resulted in statistically significant time by groups interactions in recorded step counts, self-reported completed plans and self-reported walking activities scores. The Goal-setting and feedback group and the gaming group resulted in increase in both step counts and completed plans. The results were discussed in the framework of behaviorism.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.255-260
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• 2017

In Korea, traffic accidents between pedestrians and vehicles in 2015 account for 38.8% of all accidents. This study proposes a system design that can measure the risk of conflict between a vehicle and a pedestrian. Firstly the systemdetect and estimate the position, speed, and directional data of the vehicle and the pedestrian. And then it estimate the conflict point between a vehicle and a pedestrian. The risk of conflict is quantified by estimating the pedestrian safety margin (PSM), which is the time difference between the arrival of the pedestrian at the crossing point to the point of conflict and the vehicle approaching the point. In this system each data is acquired through an external monitoring based evaluation module and an individual wearing module. In the future, such a system can be used for decision making such as the design of road hazard improvement facilities and the designation of the elderly protection area.

• Journal of the Korean GEO-environmental Society
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• v.15 no.6
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• pp.41-48
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• 2014

In this study, the behavior of fill dam with continuous water level change considering velocity changes via centrifugal model test was investigated. In addition, the collapse of fill dam due to the overflow was also experimentally simulated. The experimental results demonstrate that the pore water pressures and displacements vary in proportion to the water-level-change velocity, and the displacement increment is independent to the water-level-change velocity. Also, it is confirmed that the continuous water level change induces to the progress of fill-dam deformation due to displacement accumulation and the fill-dam stability dramatically degrades owing to the overflow. Hence, the real-time monitoring of pore water pressures and displacements of fill dam, and the control of water level in heavy rain through the countermeasure such as opening sluice gates are needed to ensure the stability of fill dam.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.51-60
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• 2008

Soil nailing systems are generally many used to the temporary structure in underground excavations and reinforcements of slopes in Korea. However, large-scaled experimental studies related to soil nailing systems are mostly studies related to performance monitoring and field pullout tests. Specially, there are no researches related in the large scaled load tests of soil nailed walls in Korea. In this study, a case study on the large scaled load tests of soil nailed walls is introduced and the behavior characteristic of them is investigated. Also, they are proposed allowable deformation corresponding to the serviceability limit of soil nailed walls and ultimate deformation corresponding to the collapse state of the walls. These results can be applied to the maintenance management of soil nailed walls. And analysis on the required minimum factor of safety of soil nailed walls using the relation curve of load ratio and deformation ratio are carried out.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5C
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• pp.523-531
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• 2003

Java applets are downloaded from web server through internet and executed in Java Virtual Machine of clients'browser. Before execution of java applets, JVM checks bytecode program with bytecode verifier and performs runtime tests with interpreter. However, these tests will not protect against undesirable runtime behavior of java applets, such as denial of service attack, email forging attack, URL spoofing attack, or annoying sound attack. In order to protect malicious applets, a technique used in this paper is java bytecode modification. This technique is used to restrict applet behavior or insert code appropriate to profiling or other monitoring efforts. Java byte modification is divided into two general forms, class-level modification involving subclassing non-final classes and method-level modification used when control over objects from final classes or interface. This paper showed that malicious applets are controlled by java bytecode modification using proxy server. This implementation does not require any changes in the web sever, JVM or web browser.