• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.9
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• pp.749-755
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• 2002

In order to develop a multi-type heat pump system with two indoor units of non-uniform capacities, the optimum refrigerant circuit was developed using capillary tubes. The refrigerant circuit was composed of four main parts, a heating circuit, a cooling circuit, a by-pass circuit and a balance circuit. The system characteristics of multi-type heat pump was investigated through the rating test and the reliability test, using the multi-type psy-chrometric calorimeter. The results of the rating test showed that the capacity of the multi-type heat pump was about 93% of the design value. In particular, the capacity of cooling single mode was about 13% higher than the design value, and the capacity of heating multi mode was about 5% higher than the design value. The reliability of the multi-type heat pump was verified by various reliability tests (overload, extension tube, freeze up, under/over charging, sweat, flood back). The optimal amount of refrigerant charge and compressor capacity were determined from the present work.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.33-38
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• 2013

Many occupational workers or professionals have to walk on the various floors for a long period of time. The objective of this study was to develop the safety shoes with increased traction through the material selection. In order to fulfill our objective, first, two kinds of filler were selected to compare the wear mechanism at outsole surface. The developed rubber materials were tested with two kinds of portable slip meters. The sample safety shoes with developed rubber materials were also tested with subject in the laboratory. During walking, the safety shoes were naturally abraded with counter surface. The coefficient of friction(COF) was gradually decreased with number of steps to 30,000, while the COF was abruptly increased from 30,000 to 40,000. The experimental results showed that COF tested with silica rubber was at least 10% higher than that with carbon black rubber in wet or detergent condition. It has been well recognized that filler properties play a important role in wet traction in the tire industry. However it has been unclear that filler properties would be decisive factor in safety shoes. Our study shows that silica exhibits a higher slip resistance than carbon black without reference to wear states in wet or detergent condition. So, this results will provide guides for outsole compounders to develop new products and improve product performance.

• Annual Conference of KIPS
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• 2002.11a
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• pp.535-538
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• 2002

InfiniBand is a switched-fabric architecture for next generation I/O systems and data centers. The InfiniBand Architecture (IBA) promises to replace bus-based architectures, such as PCI, with a switched-based fabric whose benefits include higher performance, higher RAS (reliability, availability, scalability), and the ability to create modular networks of servers and shared I/O devices. The switched-fabric InfiniBand consists of InfiniBand subnets with channel adapters, switches, and routers. In order to fully grasp the operational characteristics of InfiniBand architecture (IBA) and use them in ongoing design specification, simulation of subnet management of IBA is inevitable. In this paper, thus, we implement an IBA simulator and test some practical sample networks using it. The simulator shows the flow of operation by which the correctness and effectiveness of the system can be verified.

• Journal of Community Nutrition
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• v.7 no.4
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• pp.207-214
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• 2005

The purpose of this study is to identify the transformational or transactional leadership styles of Korean dietitians. The study was completed with Korean dietitians (n = 268, $67\%$ response) using mail survey. The leadership styles were divided into transformational (including charisma, intellectual stimulation, individualized consideration) and transactional (contingent reward, management by exception) leadership found in the several literature. Overall, the score of Korean dietitians' transactional leadership was higher than that of the transformational leadership (p < .05). Among three sub-dimensions of the transformational leadership styles, the score of 'individualized consideration' was higher than 'charisma' and 'intellectual stimulation'. Between two sub-dimensions of the transactional leadership styles, Korean dietitians used more 'management-by-exception' than 'contingent reward'. ANOVA results suggested that the transformational leadership was more likely to be used by the younger dietitians, while the transactional leadership was more likely to be used by the older dietitians (p < .05). Data showed that dietitians having 3-6 year dietetic experience used more transformational leadership than other experienced dietitians (p < .05). It was also found that the Korean dietitians' leadership styles were influenced by the type of dietetic practice area. Data showed that 'charisma', 'intellectual stimulation', 'individualized consideration' and 'contingent reward' were more likely to be used by Korean dietitians from school than by dietitians from health. care and industry (p < .05). This study will be useful for dietitians to guide the application of appropriate leadership style in order to increase employees' job satisfaction as well as organizational performance. (J Community Nutrition 7(4) : $207\∼214$, 2005)

• Journal of the Korean Society of Food Culture
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• v.34 no.5
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• pp.534-542
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• 2019

This study aimed to provide insight into methods for activating management of traditional markets by understanding differences in merchant perception according to whether or not the merchant has participated in management activation education. Analysis of merchants' levels of perception of market activation found that educated merchants had a higher perception of pre-post modernization satisfaction, promotion of traditional market revitalization projects, and post-support changes in sales. In a co-marketing context, educated merchants showed significant differences in onnuri gift certificates, bargain sales, festivals and events, and advertisement promotions. With regards to perception of management performances, educated merchants showed statistically significant higher responses for items such as satisfaction with the current vendor, increased sales, and increased customer awareness. The results in this study may be incorporated into the policy-making processes of the government or local governments in order to revitalize traditional markets, and merchant education for activation of management is deemed to be continuously necessary.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.488-495
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• 1994

To evaluate the feasibility of transmucosal delivery of leucine enkephalin (Leu-Enk) and its synthetic analog, $[D-Ala^2]$-leucine enkephalinamide (YAGFL), their physicochemical stabilities in aqueous buffered solutions were first investigated using a stability indicating high performance liquid chromatography. The degradation of Leu-Enk and YAGFL followed the pseudo-first-order kinetics. From the pH-rate profiles, it was found that the maximal stability of the two pentapeptides was at the pH of about 5.0. The shelf lives $(t_{90%})$ for the degradation of Leu-Enk and YAGFL at pH 5.0 and $40^{\circ}C$ were found to be 48.13 and 50.9 days, respectively. From the temperature dependence of the degradation, activation energies for Leu-Enk and YAGFL were calculated to be 13.61 and 13.47 kcal/mole, respectively. A higher ionic strength and a higher initial peptide concentration in buffered solution slowed the degradation of the two pentapeptides. The addition of 2-hydroxypropyl-${\beta}$-cyclodextrin into the peptide solution did not affect the stability significantly.

• Computers and Concrete
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• v.20 no.6
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• pp.655-661
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• 2017

Fiber reinforced concretes exhibit higher tensile strength depending on the percent and type of the fiber used. These concretes are used to reduce cracks and improve concrete behavior. The use of these fibers increases the production costs and reduces the compressive strength to a certain extent. Therefore, the use of fiber reinforced concrete in regions where higher tensile strength is required can cut costs and improve the overall structural strength. The behavior of fiber reinforced concrete and normal concrete adjacent to each other was investigated in the present study. The concrete used was self-compacting and did not require vibration. The samples had 0, 1, 2 and 4 wt% polypropylene fibers. 15 cm sample cubes were subjected to uniaxial loads to investigate their compressive strength. Fiber Self-Compacting Concrete was poured in the mold up to 0, 30, 50, 70 and 100 percent of the mold height, and then Self-Compacting Concrete without fiber was added to the empty section of that mold. In order to investigate concrete behavior under bending moment, concrete beam samples with similar conditions were prepared and subjected to the three-point bending flexural test. The results revealed that normal Self-Compacting Concrete and Fiber Self-Compacting Concrete may be used in adjacent to each other in structures and structural members. Moreover, no separation was observed at the interface of Fiber Self-Compacting Concrete and Self-Compacting Concrete, either in the cubic samples under compression or in the concrete beams under bending moment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.49-55
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• 2020

In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.297-304
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• 2021

In a duopoly situation, one firm can gain competitive advantage by attracting the price-sensitive customers from its competitor leading to higher profits through higher sale revenue for the competing company. A simulation study in which there are two electric car manufacturers with agent based modelling was conducted in order to verify this contention. The first step consisted of defining the baseline. Simulations of 1000 times and agent-based modelling were conducted with the assumption that company 1 reduced its price to the maximum of 20% thereby contributing to the switch-over of a maximum of 40% of the price sensitive customers of company 2. The results of 1000 simulations and agent-based modelling highlighted that price reduction by company 1 resulted in a significant increase in the number of customers, presumably due to switch-over from company 2 and there was a corresponding increase in revenues from both of the sales avenues. Thus, Company 1 achieved competitive advantage by marketing its cars to the customers of Company 2 using price reduction strategy to attract them. This study has ramifications for companies that aim to sway the price sensitive customers from a competitor.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.651-660
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• 1996

The purpose of this study was to examine and analyze the degrees and the influence factors of job satisfaction of dietitians working in hospitals in relation to performance of duty in their works and to provide effective management of hospital dietitians for high quality health and food service in hospital. The questionaire was prepared with reference to the previous studies on job satisfaction of dietitians working in hospitals throughout the nation. 201 dietitians in the country were surveyed. The period of research was from January 20 to February 28, 1995. The results are as follows. 1) In regard to the degree of job satisfaction of hospital dietitians, they showed the highest degree of job satisfaction in the relationships with fellow dietitians followed by worth and self-confidence, aptitude and interests, relationships with cooks, job stability, degree of recognition of the dietitians competence, supervision of the superiors, degree of application of professional knowledge, work load, wage level, degree of recognition of the importance of duty, cooperative relationships with load, wage level, degree of recognition of the importance of duty, cooperative relationships with doctors, degree of performance of clinical work, the number of dietitians, the prromotion system, and welfare system in that order. On the other hand, they showed the highest dissatisfaction with food service facilities. 2) The influence factors on job satisfaction are as follows. (1) Wage factor : Shorter weekday working hours and higher bonuses make greaster job satisfaction (R2=0.3115). (2) Working condition factor : Larger number of monthly holidays(R2=0.5142), shorter weekday working hours(R2=0.1077), longer previous food service experience and computer utilization (R2=0.1432) make greater job satisfaction. (3) Welfare factor : Welfare system (R2=0.4132) and promotion system (R2=0.1624) have to do with computer utilization. Job stability has to do with marital status and computer utilization (R2=0.1165). consequently, those married dietitians who use computers show higher job satisfaction. (4) Human relationship factor : Smaller mumber of patients receiving food makes greater job satisfaction (R2=0.1334). (5) Superivision factor : Shorter weekday working hours and larger number of monthly holidays make greater job satisfaction (R2=0.1709). (6) Achievement factor : Marriage, larger number of dietitians(R2=9.2293), age, larger number of monthly holiday, higher monthly wages and computer utiliazation (R2=0.1088) make greater job satisfaction. (7) Speciality factor : Marriage, longer current hospital tenure, higher position and working in seoul(R2=0.1142) make higher job satisfaction. (8) Job inclination factor : working in general hospitals rather than in oriental hispitals, working in seoul(R2=0.1776) and better bonuses(R2=0.1078)make greater job satisfaction. As a result, the following is suggested for the job satisfaction of hospital dietitions on the basis of this study : hospital dietitians can achieve miximum job satisfaction through smooth relationships with coworkers, and the responsible managers should improve welfare and working conditions for the job satisfaction of hospital dietitians.