• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.86-95
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• 2014

Productivity improvement of a shipbuilding company depends on how efficiently its limited resources are managed and utilized. Recently, research on modeling and simulation (M&S) to support shipyard production management system has been being under study. The production management based on M&S rejects decision making on experience, and it can establish productivity improvement method based on quantitative and specific data. In this paper, M&S is applied to the long-term plan as a part of the production planning in shipyards. To this end, the long-term plan processes and related management systems are analyzed. Based on the analysis, a simulation model and an application system using commercial simulation software are suggested. And basic structure of the suggested system is based on web technology such as Rich Internet Application, web services protocol for compatibility with existing shipyard enterprise systems. Utilizing the results of this study, it is expected that shipyard production planners can settle down work flow, in which one can establishes the production plan, simulates the plan, and analyzes the results, enabling a more reliable production plans.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.

• Journal of the Korean Regional Science Association
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• v.37 no.3
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• pp.19-36
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• 2021

This study examined the determinants of change in residential size according to the patterns of residential mobility in the Seoul Metropolitan Area. Particularly, this study examined the upward and downward in residential size, which is emerging as an important factor in the era of increasing non-face-to-face environment. For the empirical analysis, I used 「2018 Korea Housing Survey」 and employed binary logistic regression model. The empirical analysis shows the change of residential size is statistically significant depending on the direction of geographic. In addition, there are differences in the determinants of change in residential size. When people move within Seoul, housing factors, accessibility, age of residents, and the number of household members can be the determinants. When people move from Seoul to Gyeonggi or Incheon, housing factors, safety, gender, and the number of household members work as determinants. On the other hand, when moving from Gyeonggi or Incheon to Seoul, whether it is studio or not, housing type, accessibility, the number of household members, and the disability of homeownership are the determinants. When moving within Gyeonggi or Incheon, housing factors, Accessibility to green areas, safety, age of resident, income, and the number of household members, are the determinants.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.468-475
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• 2019

An end-line flame arrester allows free venting in combination with flame protection for vertical vent applications. End-line flame arresters are employed in various fields, especially in shipping. In flame arresters, springs are essential parts because the spring load and the spring's elasticity determine the hood opening moment. In addition, the spring has to work under a high-temperature condition because of the burning gas flame. Therefore, it is necessary to analyze the mechanical load and elasticity of the spring when the flame starts to appear. Based on simulations of the working process of a specific end-line flame arrester, a thermal and structural analysis of the spring is performed. A three-dimensional model of a burned spring is built using computational fluid dynamics (CFD) simulation. Results of the CFD analysis are input into a finite element method simulation to analyze the spring structure. The research team focused on three cases of spring loads: 43, 93, and 56 kg, correspondingly, at 150 mm of spring deflection. Consequently, the spring load was reduced by 10 kg after 5 min under a $1,000^{\circ}C$ heat condition. The simulation results can be used to predict and estimate the spring's load and elasticity at the burning time variation. Moreover, the obtained outcome can provide the industry with references to optimize the design of the spring as well as that of the flame arrester.

• Korean Security Journal
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• no.26
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• pp.121-144
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• 2011

The Framework Act on the Management of Disasters and Safety 2004(FAMDS) currently underpins Korean civil protection system, and under this FAMDS, Korean civil protection establishes a three-tiered government structure for dealing with crises and disasters: central government, provincial & metropolitan government, and local government tiers. In particular, the concept of Integrated Emergency Management(IEM) emphasizes that emergency response organizations should work and act together to respond to crises and disasters effectively, based on the coordination and cooperation model, not the command and control model. In tune with this trend, civil protection matters are, first, dealt with by local responders at the local level without direct involvement of central or federal government in the UK or USA. In other words, central government intervention is usually implemented in the UK and the USA, only when the scale or complexity of a civil protection issue is so vast, and thus requires a degree of central government coordination and support, resting on the severity and impact of the event. In contrast, it appears that civil protection mechanism in Korea has adopted a rigid centralized system within the command and control model, and for this reason, central government can easily interfere with regional or local command and control arrangements; there is a high level of central government decision-making remote from a local area. The principle of subsidiarity tends to be ignored. Under these circumstances, it is questionable whether such top-down arrangements of civil protection in Korea can manage uncertainty, unfamiliarity and unexpectedness in the age of Risk Society and Post-modern society, where interactive complexity is increasingly growing. In this context, the study argues that Korean civil protection system should move towards the decentralized model, based on coordination and cooperation between responding organizations, loosening the command and control structure, as with the UK or the USA emergency management arrangements. For this argument, the study basically explores mechanisms of civil protection arrangements in Korea under current legislation, and then finally attempts to make theoretical suggestions for the future of the Korean civil protection system.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.271-279
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• 2007

Ship structures are basically an assembly of plate elements and estimation load-carrying capacity or the ultimate strength is one of the most important criterion for estimated safety assessment and rational design on the ship structure. Also, Structural elements making up ship plated structures do not work separately against external load. One of the critical collapse events of a ship structure is the occurrence of overall buckling and plastic collapse of deck or bottom structure subjected to longitudinal bending. So, the deck and the bottom plates are reinforced by a number af longitudinal stiffeners to increase their strength and load-carrying capacity. For a rational design avoiding such a sudden collapse, it is very important to know the buckling and plastic behaviour or collapse pattern of the stiffened plate under axial compression. In this present study, to investigate effect af modeling range, the finite element method are used and their results are compared varying the analysis ranges. When making the FEA model, six types of structural modeling are adopted varying the cross section of stiffener. In the present paper, a series of FEM elastoplastic large deflection analyses is performed on a stiffened plate with fiat-bar, angle-bar and tee-bar stiffeners. When the applied axial loading, the influences of cross-sectional geometries on collapse behaviour are discussed. The purpose of the present study is examined to numerically calculate the characteristics of buckling and ultimate strength behavior according to the analysis method of ship's stiffened plate subject to axial loading.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.1-10
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• 1999

The north-west sea area of Cheju Island is where originate two layer current in the summer season. The case of the fishing operations in this sea area is almost impossible for normal expansion of the net gear for shooting net, and is happened to be frequent occasions for rise of tension suddenly in purseline by changes of the net shapes in the operation. Therefore, the safety of the operations is often obstructed by the above mentioned. In connection with the above, model experiments on the purse seine in the circulating water tank was carried out in comparison and analysis on the changes of tension in the pruseline by deformation of purse seine in the sea area of two layer current. THe results obtained are as follows;In the case of the required time for pursing of 20 minutes in the no current set, the increasing curve for tension of purseline can be expressed as:Y=0.0004x3+0.0098x2+0.3000x(r=0.9989)where Y is tension(metric tons) of a purseline, x is required time(minutes) for pursing. And, the maximum value of tension in this time was an increase of 31.3 percent at 15 minutes, and was a decrease of 30.3 percent at 30 minutes than that of 20 minutes.When the bottom margin of net is held on the position in velocity of 0.5 knot at three-eighths of net in the bottom current to the net height, the maximum tension of the required time for pursing of 30 minutes in tight set and loose set were decrease of 29.5 percent and 28.7 percent respectively than that of 20 minutes.The work load during the required time for pursing of 20 minutes were calculated 5.79×106 kgf·m in no current set, 7.89×106 kgf·m in tight set and 5.15×106 kgf·m in loose set, therefore it was an increase of 22.3 percent in tight set, and was a decrease of 11.1 percent in loose set than that of the no current set. Where tight set and loose set is a range of the bottom current with velocity of 0.5 knot at three-eighths of net to the net height.

• Korean Security Journal
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• no.12
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• pp.309-333
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• 2006

These days, the majority of public service area presents increment of utilizing a contracting-out with the following reasons such as cost-efficiency, maintenance of population changes in flexible manner, and convenience of management. The social changes have influence on policing structure and regional security system as well as problems associated with accepting the contracting-out in the public policing sector. However, many issues such as limited contracting-out sector, difficulty of encouragement of participation to private sector, and limitation of making a contract with contracting-out would be brought up when initiate contracting-out to the public policing sector. Changing security system to lower budget, planning restructure of organization, developing alterable partial contracting-out, establishing private and public cooperate system and rationalizing contract system are the suggestions to solve and modify the raising problems. This study suggests a differentiate regulation of policing services compare to currently existing contracting-out method to consider a distinctive working environment. The suggestions are as follows: 1. develop a security segregate model, 2. build a cooperative system between private and public policing sector, 3. broaden opportunity of participation of private policing sector, 4. open-competition among qualified private tender to make a contract. The private contracting-out in the public security service sector should be manage in different manner compare to other private contracting-out in government-oriented public service sector. Since work performance of each private contracting-out agency is strongly bond to safety of every civilian in the nation, it is essential to increase its standard of qualification of each agency.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.477-492
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• 2003

The purposes of the study were to establish HACCP-based standards and guidelines for conducting a plan review to build, or renovate, hospital food service establishments, and ensure the safety of foodservice and reduce the risk of food borne illness. The scope of the study included suggestion for the planning of hospital foodservice facilities: layout, design, equipment and modeling. The results of this study can be summarized as follows: 1) The development of a foodservice facility plan based on the results of a survey, literature reviews and the results of interviews with foodservice managers from 9 general hospitals. This was composed of operational policies in foodservices, layout characteristics, space allocation, selection, design, specification standards for equipment and the construction principles of foodservice facilities. 2) Two foodservice facility models were developed, one for general hospitals with 900 beds (2,000 patients and 2,500 employee meals per day) and the other for general hospitals with 300 beds (600 patients and 650 employees meals per day). 3) The suggested kitchen space requirements for the foodservice facility models were 341.2 ㎡ (W 17,100mm x L 23,700mm) and 998.8㎡ (W 35,600mm x L 32,800mm) for the 300 and 900 beds hospitals, respectively, with both designs being rectangular. The space requirements for the equipment, in relation to the total operational area, in terms of ratios were 1:3.5 and 1:3.8 for the 300 and 900 beds hospitals, respectively. The recommended space allowances per bed for the developed foodservice facility models were 1.15 ㎡ and 1.11 ㎡ for the 300 and 900 beds hospitals, respectively, which were increased by more than 30% compared to those suggested in the precedent study, and considered appropriate for the implementation of the HACCP system. 4) The hospital foodservice facilities plans and models were developed based on the general sanitation standards, guidelines and the HACCP system, and included foodservice facility layout, product flow, physical separation between contaminated and sanitary areas, foodservice facility specifications with a 1/300 scale for a 300 bed, and a 1/400 scale for a 900 beds blueprint. 5) The main features of the developed foodservice facility plans and models were; physical separation between contaminated and sanitary areas to prevent cross contamination, product flow in one direction from the arrival of the raw material to the finished product, and separation of different work areas and the process of receiving & preparation of products, refrigeration & storage, cooking, assembly, cleaning & disinfection, employee areas and janitorial facilities. The proposed models from this study were presented as examples for those wanting to build, or renovate, their facility for the production of foods.

• Journal of Society of Preventive Korean Medicine
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• v.23 no.1
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• pp.27-47
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• 2019

Purpose : This study was designed to identify the perception and practice level of infection control among korean medical doctors and to identify factors that may influence the performance and practice level. Methods : Data were collected using the on­line survey method. Seven hundred and eighty four Korean medical doctors(KMD) participated the survey. The study was conducted from December 2018 to January 2019. Results : The results of this study are as follows. 1. Participants who experienced infection risk by needles or sharp instruments were 596(76%). and participants who had experienced blood or body fluid contact with the mucous membrane or skin of the patient during treatment were 226(28.8%) of them. 2. The degree of perception and practice of the infectious guideline was higher in the group over 50 years, in the doctor group, in the group with more than 6 years experience in clinic and in the group who work in the hospital. (p < 0.05) 3. In the performance of the infection control management related to the Korean medical treatment, the practice level of the article 'Discard the remaining needle that used for one patient' was the lowest at 4.02, 'Identify the patient and check the validity period of sterilization of medicines or instruments' was the second lowest in 4.16. 4. Among the contents of "Prevention of Nosocomial infection and Sanitary Safety Guidelines" issued by the Korean Medical Association in 2008, the guideline "Prevention of infection by pathogens such as HIV, MRSA, SARS" were lowest article in the perception and practice level of participants. 5. Regression analysis was performed to find out the factors affecting perception and performance of the participants. The regression model showed significant difference in the regression model of the working years. (p < 0.05) 6. In order to examine the effect of the variables on the perception and practice of the infectious guideline, the mediated effect of the knowledge and education level according to the years of working, age, education degree was found to be significant only in the education degree variable. (p < 0.05) In conclusion : in order to improve the perception and practice of infectious control of Korean medicine doctors, it is necessary to include the contents of infection management as essential education during the continuing education of Korean medicine association.