• Structural Engineering and Mechanics
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• 제17권2호
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• pp.215-244
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• 2004

There is an ever-increasing demand for assessment of earthquake effects on transportation structures, emphasised by the crippling consequences of recent earthquakes hitting developed countries reliant on road transportation. In this work, vulnerability functions for RC bridges are derived analytically using advanced material characterisation, high quality earthquake records and adaptive inelastic dynamic analysis techniques. Four limit states are employed, all based on deformational quantities, in line with recent development of deformation-based seismic assessment. The analytically-derived vulnerability functions are then compared to a data set comprising observational damage data from the Northridge (California 1994) and Hyogo-ken Nanbu (Kobe 1995) earthquakes. The good agreement gives some confidence in the derived formulation that is recommended for use in seismic risk assessment. Furthermore, by varying the dimensions of the prototype bridge used in the study, and the span lengths supported by piers, three more bridges are obtained with different overstrength ratios (ratio of design-to-available base shear). The process of derivation of vulnerability functions is repeated and the ensuing relationships compared. The results point towards the feasibility of deriving scaling factors that may be used to obtain the set of vulnerability functions for a bridge with the knowledge of a 'generic' function and the overstrength ratio. It is demonstrated that this simple procedure gives satisfactory results for the case considered and may be used in the future to facilitate the process of deriving analytical vulnerability functions for classes of bridges once a generic relationship is established.

• Structural Engineering and Mechanics
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• 제31권1호
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• pp.11-24
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• 2009

In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both ice-resistant and economical offshore platforms. However, risk is involved in the design, construction, utilization, maintenance of offshore platforms as uncertain events may occur within the life-cycle of a platform under the extreme ice load. In this study, the optimum design model of the expected life-cycle cost for ice-resistant platforms based on cost-effectiveness criterion is proposed. Multiple performance demands of the structure, facilities and crew members, associated with the failure assessment criteria and evaluation functions of costs of construction, consequences of structural failure modes including damage, revenue loss, death and injury as well as discounting cost over time are considered. An efficient approximate method of the global reliability analysis for the offshore platforms is provided, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. The proposed life-cycle optimum design formula are applied to a typical ice-resistant platform in Bohai Bay, and the results demonstrate that the life-cycle cost-effective optimum design model is more rational compared to the conventional design.

• Asia-Pacific Journal of Business
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• 제7권1호
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• pp.11-30
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• 2016

The study specifically aimed to identify factors affecting business longevity. It focused on knowing how embroidery enterprises managed to persist in the industry for many years despite the competitive business environment. After discovering the significant relationships of such factors to longevity, problems experienced by the enterprise cluster were ascertained in order to come up with recommendations that can be proposed to the enterprise owners. Embroidery entrepreneurs have been experiencing a continuous decline in sales due to lack of innovation and intense competition. In the evaluation of their personal entrepreneurial competencies, they scored low on risk-taking, persuasion and networking, and opportunity seeking; thus, implying that these are their weaknesses. On the other hand, the statistical results of this study say that longevity is a function of the entrepreneur's competencies (i.e., persistence, commitment to work contract, demand for quality and efficiency, information seeking, and systematic planning or monitoring), the generation currently managing the business, competition, and the customer's preferences. These results suggest that these independent variables are significant and are deemed critical to business longevity. Thus, entrepreneurs have to find ways on how to use these competencies as an advantage in reinventing their businesses and in reviving their industry.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권3호
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• pp.262-276
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• 2016

Generally, the Safety Integrity Level (SIL) of a subsea Blowout Preventer (BOP) is evaluated by determining the Probability of Failure on Demand (PFD), a low demand mode evaluation indicator. However, some SIL results are above the PFD's effective area despite the subsea BOP's demand rate being within the PFD's effective range. Determining a Hazardous Event Frequency (HEF) that can cover all demand rates could be useful when establishing the effective BOP SIL. This study focused on subsea BOP functions that follow guideline 070 of the Norwegian Oil and Gas. Events that control subsea well kicks are defined. The HEF of each BOP function is analyzed and compared with the PFD by investigating the frequency for each event and the demand rate for the components. In addition, risk control options related to PFD and HEF improvements are compared, and the effectiveness of HEF as a SIL verification for subsea BOP is assessed.

• Proceedings of the Korea Society for Simulation Conference
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.101-105
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• 2002

In a traditional hierarchical inventory system, direct orders are the only information for inventory management that is exchanged between the firms involved. But due to the rapid development of modern information technology, it becomes possible for the firms to share more information in real time, e.g. demand and inventory status data. And so the term Supply Chain has emerged because it is seen as an important source of competitive advantage. Now it is possible to challenge traditional approaches to inventory management. In the past, one of the de-facto assumptions for inventory management was that the demand pattern follows a specific distribution function. However, it is undesirable to apply this assumption in real situations because the demand information in the supply chain tends to be distorted due to the bullwhip effect in a supply chain. To overcome this weakness, we propose a new solution method using NN (Neural Network). Our method proceeds in three steps. First, we find the patterns of optimal reorder points by analyzing past data. Second. train the NN using these pattern data and finally decide the reorder point. Using simulation experiment, we show that the proposed solution method gives better result than that of traditional research.

• The Journal of Korean Physical Therapy
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• 제13권1호
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• pp.107-114
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• 2001

Recently the number of elderly have been increasing at a rapid pace in Korea. Accompanying this aged society are numerous health problems. Whit this in mind health-promotion behaviors such as physical activity. good nutrition and stress management are vitally important to the elderly in reducing the risk of Health problems, maintaining health and improving the overall quality of life. Health promotion programs for the elderly must be developed. The purpose of th is study was to determine influential cognitive factors on health-promotion behaviors and the effects of previously implemented Health promotion programs. For this, previous studies were reviewed and analyzed. The results were as follows. 1. Cognitive factors on health-promotion behaviors were internal locus of control, perceived health status, self-efficacy, concerns about health, social support, attending social activities. 2. Components of health promotion programs were exercise and health education. Exercise was performed in most programs. The effects of exercise programs were improved flexibility, muscle strength. balance, cardiopulmonary function and elevated ability of daily living, perceived health status, quality of lift and a decrease depression. The results strongly suggest that complex health promotion programs should be developed. Health promotion programs need to include exercise, health education, health counseling and social activities. We have to consider cognitive factors on health-promotion behaviors.

• Toxicological Research
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• 제13권3호
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• pp.257-263
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• 1997

Pentachlorophenol(PCP) which ks widely used in wood preservation, pulp and paper mills, has led to a substantial envirortmental contamination. To get the reliable data for the effective health risk assessment with PCP, covalent binding potential of PCP to cellular macromolecules and glutathione(GSH) was investigated after intraperitoneal administration of $^{14}C-PCP$ to rats. PCP metabolites were able to bind covalently to serum albumin and hepatic protein in a dose- and time-dependent manner. Hepatic protein adducts of PCP metabolites were increased as a function of cytochrome P-450 activities, whereas, albumin adducts significantly decreased. Covalent binding of PCP metabolites with DNA or hemoglobin was not observed. GSH levels in liver tissue decreased over 12hrs, however, the level was recovered after 48hrs. Tetrachloro-1,4-benzoquinone (1,4-TCBQ), one of the most reactive PCP metabolites, conjugated with GSH very rapidly. Base on our results, we could conclude that PCP metabolized to reactive electrophilic metabolites by cytochrome P-450 isoenzymes and conjugated rapidly with neighboring protein or nonprotein sulfhydryl before reacting with DNA or hemoglobin. We propose that albumin adducts and mercapturic acids of PCP metabolites can be used good biomarker of recent PCP exposure.

• Korean Journal of Health Education and Promotion
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• 제28권5호
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• pp.35-49
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• 2011

Objectives: This article reviewed research on smoking behaviors and smoking-related health problems among university students to suggest evidences for developing smoking control strategies for them. Methods: Domestic research papers were screened through Research Information Sharing Service (RISS), Koreanstudies Information Service System (KISS), Medical Library Information System (MEDLIS), Korean Medical Database (KMbase), and digital national assembly library. International papers were searched mainly via PubMed. Results: Smoking prevalence among male college students were found to be over 50% in majority of Korean studies. While studies on smoking-related health problems were scant in Korea, several recent studies overseas showed possible effects of smoking on health among young adults, including decreased lung function, respiratory symptoms, cardiovascular problems, glucose intolerance, buccal disease, depressive symptoms, and so forth. Besides, smoking behaviors were closely related with other risk behaviors including drinking, and several psychosocial factors. Conclusions: To explore the smoking problem among college students, the first step should be a national representative survey with scientific methods. More research should be focused on the smoking-related problems among college students. To prevent smoking among college students, smoking prevention education, and smoking cessation counseling, and the initiatives of smoke free campus are needed.

• International Journal of Safety
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• 제9권1호
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• pp.30-34
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• 2010

A big difference is seen in the perception of self-responsibility concerning safety, as a result of my survey on the safety measures taken in the pipeline construction at workers level between Japan and Indonesia. Specifically, when an accident occurs, a worker in Indonesia will think that the responsibility depends on the person who causes it. However a worker in Japan will think that safety is can only be protected by law and regulations. There is also another difference in the understanding of construction period. It is alright in Indonesia to take 5 times longer period than it takes in Japan if the cost is less. The idea of punctual delivery is very strong in Japan. Through this survey, points which construction industry in Japan could learn from Indonesia came to surface. In addition, over the recent years, several nasty accidents at Japanese sites were caused due to human error to disregard the law. Japanese should arouse the awareness of self-responsibility in this regard. Risk management should be upon self-recognition of each individual worker in both countries. What is important is the "work attitude education", "to grow sense of self-responsibility by thinking on one's own for one's self" in the education curriculum of man to man learning as in technical educational program.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제26권7호
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• pp.99-109
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• 2012

Sub-station, key equipment in electric power infrastructure, are being exposed to increasing risk of hacking. For this, soft redundancy sub-station system needs to be formulated with automatic restoration mechanism. For this it is important to assess the reliability of the applicable range of data that are used in actual system operation, as well as the methods and findings of the tests. At the same time performance of soft redundancy system and total security mechanism, which are aligned for the protection of the sub-station, need to be tested. For testing the above-mentioned, this paper presented a viable formation of a soft redundancy practical VPN system within a panel to protect the latter from hacking or cracking incidences, and conducts a test to check if the considered system actually serves the protection function in the actual operation setting, gathering evidence from the data from the testing of the actual performance of the system as well as of emergency scenario simulation operations. Because tested soft-redundancy & restorative sub-station system is expected to be widely applicable for various cases such as Smart-grid or electricity IT system, where VPN with enhanced level of security is required.