• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.241-251
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• 2010

The purpose of this study is to identify the difference of stress amount depending on the characteristics of hospital workers and job-stress's influence on the stress-measurement fields. For this purpose, the study surveyed 475 workers in 9 hospitals (2 general hospitals and 7hospitals) in Busan and empirically analyzed the data collected from them. In terms of theory and practice, the result of this study suggests as follows: First, there is significant difference in the stress amount depending on worker'scharacteristics.Second, the stress-measurement field with the largest influence on the job-stress is the job requirement, and the lowest field is the hospital culture. Third, at comparing the job stress amount with those of average Koreans, the stress-requirement field occupies the upper 50% zone for male, and the job-instability forfemale. As the result of this study, it is recognized that the structure management of medical institutions must consider the different stress factors according to the workers characteristics.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.8
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• pp.730-740
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• 2000

The software rejuvenation method for highly available multiplex systems uses a pro-active fault-tolerant approach to handle system failures. The software rejuvenation prevents failures from occurring, while the previous methods recover from failures after happening. Especially, since the software aging proceeds fast in the software used for the multimedia mobile computing due to the loss of communications or data, the preventive method from failures using software rejuvenation can be used for the multimedia mobile computing. In this paper, according to the operational parameters such as rejuvenation period, rejuvenation time, failure rate and repair rate of the servers, number of running servers, duration of running time, and type of running modes, we calculate steady-state probabilities, downtime, availability, and cost of the multiplex systems using software rejuvenation method. We validate the closed-form solutions of the mathematical model by experiments based on various operational parameters and find that the software rejuvenation method can be adopted as preventive fault-tolerant technique. The failure rate and unstable rate of the servers are essential factors for the decision making of the rejuvenation policies.

• Korean Journal of Social Welfare
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• v.64 no.4
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• pp.113-136
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• 2012

This study profoundly analyzed cultural welfare workers to find out how they command a strategy of empowerment according to types of action. The analysis result shows that cultural welfare workers perceive cultural welfare as an unstable human service job. Activity types of cultural welfare workers can largely be categorized into professional workers and vocational workers, and they are two extremes and continuum at the same time. On this account, a strategy of empowerment depends on types of action conducted by cultural welfare workers. There are accelerative elements that boost empowerment strategies positively and there are impediment elements that work adversely. These cultural welfare workers are making suggestion to prepare an official requirement for them to be acknowledged as a specialized worker and to increase various types of educational spectrum to meet their level. This study has significance for providing basic data for education, supervision, and policy for training human resources in future.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.81-89
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• 2018

In this study, the operating characteristics of a small-scale pulse detonation engine (PDE) were investigated experimentally for application as a small thruster and an igniter. The PDE was constructed using commercial gas tubes with an inner diameter of 4.22 mm. The operating and detonation propagation characteristics of the PDE were investigated over the ranges of equivalence ratios and operating frequencies. Measured detonation speed was close to 10% of the theoretical CJ values at 1 Hz and 5 Hz conditions. However, unstable propagation characteristics were shown at 20 Hz and lean conditions, where the velocity deficit was increased by 20~62%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.211-216
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• 2012

Control Theory for continuous-time system has been well developed. Due to the development of computer technology, digital control scheme are employed in many areas. When delays are in control systems, it is hard to control the system efficiently. Delays by controller-to-actuator and sensor-to-controller deteriorate control performance and could possibly destabilize the overall system. In this paper, a new approximated discretization method and digital design for control systems with multiple state, input and output delays and a generalized bilinear transformation method with a tunable parameter are also provided, which can re-transform the integer time-delayed discrete-time model to its continuous-time model. Illustrative example is given to demonstrate the effectiveness of the developed method.

• Korean Business Review
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• v.11
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• pp.439-464
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• 1998

Global electronic commerce, driven by the development of the Internet and computer, premises to be an important engine for growth for the world economy in the 21st century. Electronic commerce offers considerable new opportunities for businesses and citizens in all regions of the world by enhancing productivity across all sectors 6f our economies and encouraging trade in both goods and services. Specially in relation to contract, electronic commerce requires a coherent, coordinated approach internationally on key issues such as a validity, a legality, consumer protection. In order to ensure the stable growth of electronic commerce in Korea, the government needs to construct a predictable legal and commercial environment, suitable to the situation in Korea, for business conduct on the Internet and other electronic method. Electronic commerce, which breaks down national boundaries and widens the gap between the place where services are performed and the place where they are consumed, requires a new paradigm when making an agreement between contracting parties.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.251-260
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• 2017

The option pricing of Black와 Scholes (1973) and Merton (1973) has been widely reported to fail to reflect the time varying volatility of financial time series in many real applications. For example, Duan (1995) proposed GARCH option pricing method through Monte Carlo simulation. However, financial time series is known to follow a fat-tailed and leptokurtic probability distribution, which is not explained by Duan (1995). In this paper, in order to overcome such defects, we proposed the option pricing method based on GARCH models with normal mixture errors. According to the analysis of KOSPI200 option price data, the option pricing based on GARCH models with normal mixture errors outperformed the option pricing based on GARCH models with normal errors in the unstable period with high volatility.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.243-249
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• 2010

The competition between ship management companies is fierce as a result of global trend towards increased specialization. In order for ship management companies to remain competitive, it is necessary to understand the local and global factors and the changing circumstances that impact shipping markets and trade patterns. To better understand these factors, a study and analysis of drawing priority of the competitiveness-evaluation factors of ship management companies was conducted using Analytical Hierarchy Process(AHP) as a method dealing with dicision-making problem. As a consequence of this analysis, it was determined that human resources, both shipboard and land management, were a primary factor in ship management company's competitiveness. Thus, the acquisition and retention of capable staff was a key aspect of assuring a ship management company's competitiveness.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.38-42
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• 2003

For the purpose of developing new agrochemical fungicides, compound 2 possessing 1,3-thiazole scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazoline based on isosterism. The reaction of N-methylthiouea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazole 4 regioselectively, which was treated with phenyl isocyanates to give the corresponding 7 which is tautomer of 2. The structural assignment of 7 was confirmed by various spectra($^1H$ NMR, $^{13}C$ NMR, FT-IR, HRMS), and X-ray crystallographic data. Compound 8 which is a structural isomer of 7 was formed through thermodynamically unstable intermediate 2,4-diimino-1,3-thiazole 6.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.89-94
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• 2010

Fuselage propellant feeding system should supply propellants to engine with required flow rate, temperature and pressure. Propellant vibration in engine and feeding line changes feeding characteristics, and frequently inhibits to satisfy the required feeding requirements. Sloshing and POGO vibration are known to be the major vibration phenomena. Concerning sloshing and POGO, vehicle control and structural dynamics aspects are extensively studied, whereas, its effect on propellant feeding performance is not clearly understood. This paper focuses on the deviation of required feeding performance due to propellant vibration. Overall characteristics of propellant vibration and its effect on propellant supply to engine are reviewed and control mechanism for suppressing vibration is introduced.