• Journal of the military operations research society of Korea
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• v.29 no.2
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• pp.100-110
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• 2003

Equipment replacement policy may not be defined with certainty, because physical states of any technological system may not be determined with foresight. This paper presents Markov Decision Process(MDP) model for army equipment which is subject to the uncertainty of deterioration and ultimately to failure. The components of the MDP model is defined as follows: ⅰ) state is identified as the age of the equipment, ⅱ) actions are classified as 'keep' and 'replace', ⅲ) cost is defined as the expected cost per unit time associated with 'keep' and 'replace' actions, ⅳ) transition probability is derived from Weibull distribution. Using the MDP model, we can determine the optimal replacement policy for an army equipment replacement problem.

• Journal of Navigation and Port Research
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• v.36 no.2
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• pp.131-140
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• 2012

Since 2000, S. Korea is building yachts through government supported localization, cooperation between industry and educational organizations, or partnerships with foreign firms but the yacht building has yet only accomplished trial manufactured ships and one-time production. Because of a lack of mass production, the industry assesses the domestic technical skills to an average 50~60% of developed countries and its market share is less than 1% in the world. In addition, domestic marine equipment is heavily depending on imports and the industry is experiencing shortage of technology and experts, small-sized companies, insufficient industry and educational organizations' cooperation networks, inadequate legislation and policies, deficient domestic market vitalization, and scarce international information. Thus, this study focuses on the alternative plans to strengthen competitiveness and to cope with problems in the southeast marine leisure equipment industry.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.177-185
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• 1999

This paper deals with the case study that determine the best equipment scale to be satisfied a handing capacity of the container terminal using computer simulation techniques. The objective of this study is to suggest an operation alternative of equipment scale including container canes, transfer cranes, and yard tractors which reflects a container throughput. For the simulation, the object-oriented simulator with the special purpose of container terminal analysis is used. And the used simulator was developed to simulate the transfer crane based container terminal for yard equipment. Using the simulator, we test an existing port container terminal, PECT(Pusan East Container Terminal).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.460-471
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• 2019

The aim of this study was to examine the scale and market share of Chinese's research facility & equipment in the domestic research equipment market of basic and analytical science field for analyzing the difference of the number and amount of construction by year of acquisition, national research facility equipment standard classification code, and type of institution based on the information of the research equipment invested by the Korean government for the past 14 years. In addition, we analyzed the correlation among the year of acquisition, equipment standard classification code, and type of institution variables. As of January 1 2019, from 2005 to 2018, 50 Chinese's research facilities & equipments (main equipment with a construction cost of 30 million won or more) built in the basic and analytical science fields were selected for this study and their number of construction, amount of construction, year of acquisition, type of institution, and standard classification code were analyzed. Differences of the number and amount of construction with-in and by year of acquisition, standard classification code, and type of institution were tested using a single sample Chi-square test, Mann-Whitney U test, and Kruskal-wallis test. The correlation among the three variables was analyzed by using the Chi-square test of cross-tabulation analysis. And there was a statistically significant correlation among the year of acquisition, standard classification code, and type of institution (p<.05). Compared to the 2000s, in the 2010s, high-priced Optical Electronics/Video Equipment was installed at private universities, private enterprises, and government-affiliated research institute. Therefore, the domestic construction status of Chinese's research facility & equipment in the basic science and analytical science field is less than that of the domestic ones, but the number and the amount of construction are increasing statistically. So it is necessary for the government to be able to recognize the possibility that the Chinese's research facility and equipment can encroach on the domestic research industry market and to prepare related provision.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.119-131
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• 2014

For quick and accurate ground investigation in wide construction site being not easy to access, advanced dynamic cone penetration test equipment was developed based on widely used equipment abroad. Advantages of existing equipment of portability and simple testing method were reflected in the new developed equipment. Meanwhile, by extending connection of lower rod, penetration depth is raised to 6m from 1 m of the existing equipment. Moreover, by assembly of hammer (2+3+3kg) and cone (3 types) etc., it is possible to perform test under the same conditions with those by German and Japan dynamic cone penetration test equipment (Tsukuba, PWRI and SH types). Auxiliary equipment was applied to make sure of perpendicularity as penetration depth increases. Applicability of the new developed equipment was evaluated through tests on various fields and its reliability was verified.

• Journal of the Korea Institute of Construction Safety
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• v.4 no.1
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• pp.9-15
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• 2021

Recently, buildings have become larger, more complex, and various construction methods have been tried. As a result, the use of construction equipment continues to increase, as well as safety accidents. According to the Ministry of Employment and Labor's report on industrial accidents, the rate of deaths caused by construction equipment among construction accidents has been increasing steadily since 2009. In the safety field of other industries such as crime and traffic, research has been continuously conducted to develop quantitative indicators due to demands for development of evaluation indicators or risk index development. On the other hand, construction equipment has been studied to analyze disaster cases and come up with improvement measures, but there is no research related to risk index. Therefore, the research will develop a quantitative index that can determine the risk level of construction equipment in the field based on the accident case and verify the possibility of use in the field.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.293-305
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• 2015

In order to understand the mechanisms of conversion between different algal dominance, an experiment was performed in a greenhouse from 22 June to 10 July 2011. The experiment included a treatment group subjected to three instances of nutrient enrichment and a control with no nutrient enrichment. The initial water was dominated by Ankistrodesmus of Chlorophyta. The average water temperature at 08:30 h and 14:00 h during the experiment was $31.6^{\circ}C$ and $34.6^{\circ}C$, respectively. The results showed that the total nitrogen (TN), total phosphorus (TP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), and soluble reactive phosphorus (SRP) concentrations in the treatment were significantly higher than in the control (P < 0.05). However, the TN/TP and DTN/DTP in the control was higher than in the treatment (P < 0.05). The dominant algae in the control did not change during the experiment, while the dominant algae in the treatment switched to Planktothrix of Cyanophyta on day 9. The chlorophyll a (Chl-a), wet weight of all algae, wet weight of Cyanophyta, and percentage of Cyanophyta in the control were all significantly lower than in the treatment (P < 0.05). Amounts of zooplankton, especially rotifers, were present at the end of the experimental period. The density of rotifers between the control and treatment was not significantly different (P > 0.05), while the copepod density in the treatment was higher than in the control (P < 0.05). We conclude that green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in a greenhouse with elevated temperature.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1363-1373
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• 2022

The recent seismic events that occurred in South Korea have increased the interest in the re-evaluation of the seismic capacity of nuclear power plant (NPP) equipment, which is often conservatively estimated. To date, various approaches-including the Bayesian method proposed by the United States (US) Electric Power Research Institute -have been developed to quantify the seismic capacity of NPP equipment. Among these, the Bayesian approach has advantages in accounting for both prior knowledge and new information to update the probabilistic distribution of seismic capacity. However, data availability and region-specific issues exist in applying this Bayesian approach to Korean NPP equipment. Therefore, this paper proposes to construct an earthquake experience database by combining available earthquake records at Korean NPP sites and the general location of equipment within NPPs. Also, for the better representation of the seismic demand of Korean earthquake datasets, which have distinct seismic characteristics from those of the US at a high-frequency range, a broadband frequency range optimization is suggested. The proposed data construction and seismic demand optimization method for seismic capacity re-evaluation are demonstrated and tested on a 480 V motor control center of a South Korea NPP.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.2
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• pp.253-263
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• 2008

This study examined the menu management and utilization of cooking equipment at school foodservice operations in the Chonbuk area. Self-administered questionnaires were collected from a total of 193 school dietitians. Statistical data analysis was completed using the SPSS v. 11.5 program. The results are summarized as follows. Among the 193 schools, 58.5% were elementary schools and 41.5% were middle and high schools. Approximately 97% of the schools prepared meals in the conventional manner. Among the school, 68.4% had a menu cycle of 1${\sim}$2 weeks. The frequency of using convenience foods was significantly different between the elementary schools and middle and high schools(p<0.001). Approximately 45% of the dietitians responded that the most important details for menu planning were menu variety and consumer preference. However, 66.8% of the dietitians responded that a key problem for menu planning was limited and worn-out kitchen equipment. Although the cost of purchasing cooking equipment is high, most dietitians responded they have high needs for equipment in order to meet of the quantity demands of food production. In terms of utilized cooking equipment, most schools had mixers, vegetable cutters, choppers, dish washers, etc. Yet the amenities most often lacking were meat slicers, composting machines, ovens, and griddles. In utilizing the cooking equipment, there was no significant difference between the dietitians in the elementary(3.67) schools and those in the middle and high school foodservice systems(3.70); however, the utilization level was poor. Therefore, governmental regulatory agencies should review and finance support for purchasing cooking equipment. Finally, purchasing analysis was conducted regarding the dietitians' opinions on menu recipes and useful equipment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.327-331
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• 2007

Inundation of substation and underground power equipment(pad-mounted transformers & switches) breaks out every summer season in low-lying downtown and low-lying shore by localized heavy rain, typhoon and tidal wave. In case inundation of substation and underground power equipment, it occurs a great economic loss owing to recovery time and events of electric shock occur by inundation electrical facility. So we search the damage situation and installation situations. Therefore we propose the necessity of protection of flood at low-lying downtown and low-tying shore. This paper will be used to present a reform proposal of electrical related law about flood protection of existing power equipment.