• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.573-580
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• 2013

The combined effects of reactivity coefficients, along with other core nuclear characteristics, determine reactor core behavior in normal operation and accident conditions. The Power Coefficient of Reactivity (PCR) is an aggregate indicator representing the change in reactor core reactivity per unit change in reactor power. It is an integral quantity which captures the contributions of the fuel temperature, coolant void, and coolant temperature reactivity feedbacks. All nuclear reactor designs provide a balance between their inherent nuclear characteristics and the engineered reactivity control features, to ensure that changes in reactivity under all operating conditions are maintained within a safe range. The $CANDU^{(R)}$ reactor design takes advantage of its inherent nuclear characteristics, namely a small magnitude of reactivity coefficients, minimal excess reactivity, and very long prompt neutron lifetime, to mitigate the demand on the engineered systems for controlling reactivity and responding to accidents. In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity. It will be demonstrated that during Loss of Regulation Control (LORC) and Large Break Loss of Coolant Accident (LBLOCA) events, the impact of variations in power coefficient, including a hypothesized larger than estimated PCR, has no safety-significance for CANDU reactor design. Since the CANDU 6 PCR is small, variations in the range of values for PCR on the performance or safety of the reactor are not significant.

• Journal of KIISE
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• v.42 no.12
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• pp.1611-1622
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• 2015

Although Android systems provide a permission-based access control mechanism and demand a user to decide whether to install an app based on its permission list, many users tend to ignore this phase. Thus, an improved method is necessary for users to intuitively make informed decisions when installing a new app. In this paper, with regard to the permission-based access control system, we present a novel approach based on a machine-learning technique in order to support a user decision-making on the fly. We apply the K-NN (K-Nearest Neighbors) classification algorithm with necessary weighted modifications for malicious app classification, and use 152 Android permissions as features. Our experiment shows a superior classification result (93.5% accuracy) compared to other previous work. We expect that our method can help users make informed decisions at the installation step.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.295-301
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• 2006

An operational strategy for inventory control on finished goods in the distribution system has been given attention to many enterprises and many studies regarding this field have been done and is also on-going currently. It handling large scale of smallness type are so the requisition of customer which is various that over it continues more full scale merit. therefore, It is a tendency that many of enterprise is handling small scale of smallness type for environment change confrontation. but It is not easy for the enterprise to In customer demand diversification suiting because too need many cost. In addition, at enterprise charge extra weight because remainder inventory is causes of defective stock for a inefficient problem solution. this paper is rationalization of stock cost decrease for comparison evaluation of small scale quantify handling of singleness type and small scale quantity handling of largeness type.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.272-282
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• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.

• Korean Journal of Occupational Health Nursing
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• v.15 no.2
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• pp.115-125
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• 2006

Purpose: This study analyzed the amount of stress and the different effects according to the working times(hours) of a week in two groups: more than 40 hours a week and less than 40 hours a week. Method: The study was conducted from November 1st 2005 to December 15th 2005. The purpose of the study has already been explained in the experiment objectives. 20 copies of evaluation forms were sent by mail to 50 different health sections of participating work sites. A total of 1,000 copies were sent out and 870 were sent back. Within the forms, sent back 120 copies had insufficient data, so 750 copies of evaluation forms were analyzed. Result: Working stress for under 40 hours of working time showed a total of 46.10 points and 47.18 for over 40 hours of working time. For over 40 hours, job demand and occupational climate was high and under 40 hours showed a high rate of job control. For under 40 hours of working time, the factors that caused stress were female, irregular diet habit, age of 30's, nonmanufacturing, and single. For over 40 hours of working time, the factors that causes stress were age of over 40, when the number of employees is 500~999, high rate of fatigue, when the position of the employee is higher then section chief, and when the work amount is high. Conclusion: The stress rate showed significantly higher in over 40 hours of working time. Therefore, adequate working hour distribution and health promotion programs are needed. The factors that cause stress in both under and over 40 hours of working time differed. Therefore, a distinguished program to control work stress for additional working time is needed.

• Korean Journal of Health Education and Promotion
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• v.32 no.5
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• pp.63-72
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• 2015

Objectives: The aim of this study was to evaluate the relationship of occupational stress and psychosocial stress to health promotion behaviors depending on characteristics of female office workers and emotional labor workers for sales. Methods: A survey of 207 female service workers engaging in sales of cosmetics in major department stores and 149 females working in the offices of cosmetics companies was carried out using a self-administered questionnaire. Results: It showed a significant difference in job demand and insufficient job control which are sub-domains of stress. The percentage of emotional laborers exposed to a high risk of psychosocial stress was higher than office workers. In office workers, occupational stress stemmed from insufficient job control and low reward of work was significantly related to psychosocial stress. But in emotional labor workers, stress from job insecurity, and organizational system were added. The relevant factors that affect health promotion behaviors were type of occupational stress, psychosocial stress, marital status, educational level and working career. Conclusions: Occupational stress and psychosocial stress were closely associated with health promotion behaviors. It was suggested that the development of health promotion programs which reduce the stress in female office and emotional labor workers.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.9
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• pp.273-278
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• 2014

Recent use of electricity during peak hours electricity supply-demand imbalance is inevitable that limit power use force. Therefore, in this paper, a circuit of parallel power operation equipment for peak power reduction which saves the power to electricity storage device during the non-peak power time and supply from the storage power during the expected power shortages time is designed Through this circuitry, the peak power of the commercial power supply with the parallel operation and connection of the commercial power supply and the power supply of the inverter from electricity storage that is a key feature of PRS(Peak power Reduction System) can be controlled. In addition, in order to increase the efficiency, a Transless Power Circuit DC-AC inverter is developed. Moreover, a variable impedance control is applied to the storage of electric power of an Uninterruptible Power Supply associated with a commercial power source.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.749-756
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• 2011

Recently, ever-growing land price has caused public projects to come to considerable deadlocks. Up to date, project principals have relied upon mandatory expropriation policy or other relevant policies in order to procure land sites required for public projects in a short period, but these policies have brought about collective resistances and civil appeals from land owners and cause land compensation price to rise, resulting in delayed progress of public projects. Therefore, land banking system is enforced to resolve these issues. Successful implementation of land banking system requires purchase of sufficient land sites at affordable price so as to execute public projects and control real estate market. However, current version of Land Banking Act reveals several questions as contrary to public expectations in the days of its introduction. This study sought to make further analysis on the whole content of current legal system concerning land banking system. And based on the analysis, this study explored possible solutions for problems that hinder land banking system from its stable operations, so that this land banking system could contribute to resolving land problems by active promotion of public projects as originally intended and by the stabilization of land market based on balance control between supply and demand of land.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1479-1485
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• 2012

The parking management system can increase driver's convenience with detailed parking information service in the parking lot. At the same time, parking management system consumes non-negligible electrical energy with large amount of sensors, displays and control modules. With the increase in the demand for green and sustainable building design all over the world, it becomes a meaningful issue for parking management system to reduce operating power. This paper presents the preliminary design and estimated results of a parking management system which is optimized to reduce the power consumption mainly on detectors and displays. The system design is based on pre-developed wireless parking detectors, Park Tile and Park Disk. The system has a number of parking space detectors, vehicle count detectors, information displays, guidance terminals and other control units. We have performed system architecture design, communication network design, parking information service scenario planning, battery life regulation and at last operating power estimation. The estimated operating power was 0.93KW per parking-slot, which is 20% of traditional systems. The estimated annual maintenance cost was 18% of traditional systems.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1038-1043
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• 2015

When the study on the relationship between the Head-of-Bed (HOB) angle and ventilator-associated pneumonia is performed, the fact that the HOB angle can only be measured intermittently imposes a significant limitation on the study. Therefore, there has been demand for the development of a device that can measure the HOB angle continuously. In this paper, we propose the rapid prototyping of an HOB measurement system using open-source hardware and software. The proposed system helps to maintain the HOB angle at a particular angle by displaying the angle and helps the medical study of pneumonia patients by enabling continuous data acquisition. Firstly, we eliminate the process of making an MCU board by utilizing an open-source hardware mbed LPC1768. Secondly, we reduce the software development time by using libraries and hence enabling the easy use of peripherals. Thirdly, for rapid prototyping, we build the enclosure of the proposed system using a 3D printer. The proposed system can be attached and detached to and from a bed. Therefore, we can attach it to the bed of a patient for whom measurement of the HOB angle is necessary. Finally, we check the measurement performance and the validity of the proposed system through an experiment utilizing an incremental encoder.