• Tunnel and Underground Space
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• v.15 no.4 s.57
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• pp.275-287
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• 2005

At the planning and design stages of a development of underground space or tunneling project, the information regarding ground conditions is very important to enhance economical efficiency and overall safety In general, the information can be expressed using RMR or Q-system and with the geophysical exploration image. RMR or Q-system can provide direct information of rock mass in a local scale for the design scheme. Oppositely, the image of geophysical exploration can provide an exthaustive but indirect information. These two types of the information have inherent uncertainties from various sources and are given in different scales and with their own physical meanings. Recently, RMR has been estimated in unsampled areas based on given data using geostatistical methods like Kriging and conditional simulation. In this study, simulated annealing(SA) is applied to overcome the shortcomings of Kriging methods or conditional simulations just using a primary variable. Using this technique, RMR and the image of geophysical exploration can be integrated to construct the spatial distribution of RM and to evaluate its uncertainty. The SA method was applied to solve an optimization problem with constraints. We have suggested the practical procedure of the SA technique for the uncertainty evaluation of RMR and also demonstrated this technique through an application, where it was used to identify the spatial distribution of RMR and quantify the uncertainty. For a geotechnical application, the objective functions of SA are defined using statistical models of RMR and the correlations between RMR and the reference image. The applicability and validity of this application are examined and then the result of uncertainty evaluation can be used to optimize the tunnel layout.

• Journal of Korean Society of Disaster and Security
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• v.7 no.2
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• pp.17-24
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• 2014

Recently, many accidents occur frequently because sprinklers aren't installed or don't work right when there are outbreak of fire in houses and aggregate buildings. Therefore, they can result in damage for humans and loss of property. Sprinklers are the most appropriate which can extinguish buildings' fire in the initial stages. Through lack of legal system, in domestic cases, sprinklers cannot operate their inherent performance. Domestic standard simply classifies installation objects according to types of business and forms of buildings, also divides into uses and floors of buildings. Especially it only regulates that sprinklers must be installed every floors in particular fire buildings that have more than eleven floors. While it doesn't need to install sprinklers below ten floors, so we are threatened the safety. In this study, we derived causes and implications by analyzing concepts of sprinklers facilities, installation standards in domestic and foreign legal system, and recent cases that expanded damages in fire accidents because of weak point of installation and control standards. In domestic cases, as a result, government has to provide an institutional strategy and law that regulate duty to install sprinklers to all aggregate buildings regardless of floors in terms of new buildings. Also, if someone who has existing buildings wanted to install them, government would guarantee subsidy to encourage installation. In addition, government supervises fire-fighting activities when there are fire by compensating standards about regular inspection by a qualified technician, operation and maintenance of sprinklers as well as reinforcement of administrative criteria.

• Archives of design research
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• v.11 no.3
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• pp.219-228
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• 1998

As automobile drivers' desires become ever diversified with the spreading phenomenon of 'characteristic automobile decorations', it is feared that the design quality may be deteriorated, while the safety be retarded in terms of performance and function. In Korea, the 'Dress-up tuning' becomes the source of the social criticism because of lack of relevant codes and professional tuning services, while automobile drivers are excessively having their automobiles overdressed ignoring the overall aesthetic aspect and functions. Under such a circumstance, this study was aimed at reviewing the practices and dress-up accessories by each automobile part of those foreign automobile makers and professional tuners who have introduced the concept of 'customizing' and developed dress-up accessories and various tuning parts only to satisfy their customers' tuning needs. It is anticipated that automobile styling would tend more to pursue a 'coordination' featuring ordinary consumers' individualistic senses, while customers' needs reflecting their life styles be more refined. Meanwhile, Korean automobile consumers have accommodated the product designs : presented within the producers' frameworks, but they are expected to pursue the design values varying according to changing structures of production, society and industry as well as the resultant design activities. In all, makers and designers are requested to be aware of such changing environment structures and thereby, explore other alternatives, or reflect seriously on the socio-cultural implications inherent in the products, namely on the production and consumption of people's favorites.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.15-23
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• 2015

In the construction industry, risk management has gained constant attention as the factor not only to evaluate global competitiveness of the country but also to secure competitiveness of public institutions and private companies. For effective construction risk management, the specific work process improvement that can be employed in the field in terms of risk management of the entire corporation such as financial, insurance and safety management is necessary. To manage construction risks, what is important is the step to identifying inherent risks in the construction project. The identification of risks will be followed by the step to seeking ways to establish and manage strategies responding to the risks. This study suggests ways and processes to make a checkslit to identify risks through case studies. To that end, the focus will be placed on working process improvement of risk identification among stages to manage construction risks such as risk identification and analyses, planning to respond to risks, risk monitoring and management. The case study checklists show that setting up the system to classify risks by stage is helpful to figure out causes of risks to reduce or eliminate risk factors. The checklist making process that considers features of the project is expected to contribute to successful completion of the project by enabling effective risk identification and systematic risk management.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1421-1426
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• 2014

To improve the inherent safety of the sodium-cooled fast reactor (SFR), the supercritical $CO_2$ ($S-CO_2$) Brayton cycle is being considered as an alternative power conversion system to steam the Rankine cycle. In the $S-CO_2$ system, a PCHE (printed circuit heat exchanger) is being considered. In this type of heat exchangers, diffusion bonding is used for joining the thin plates. In this study, the diffusion bonding characteristics of various austenitic alloys were evaluated. The tensile properties were measured at temperatures starting from the room temperature up to $650^{\circ}C$. For the 316H and 347H types of stainless steel, the tensile ductility was well maintained up to $550^{\circ}C$. However, the Incoloy 800HT showed lower strength and ductility at all temperatures. The microstructure near the bond line was examined to understand the reason for the loss of ductility at high temperatures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1415-1420
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• 2014

Super-critical $CO_2$ ($S-CO_2$) Brayton cycle has been considered to replace the current steam Rankine cycle in Sodium-cooled Fast Reactor (SFR) in order to improve the inherent safety and thermal efficiency. Several austenitic alloys are considered as the structural materials for high temperature $S-CO_2$ environment.. Microstructural change after long-term exposure to high temperature $S-CO_2$ environment could affect to the mechanical properties. In this study, candidate materials (austenitic stainless steels and Alloy 800HT) were exposed to $S-CO_2$ to assess oxidation resistance and the change in tensile properties. Loss of ductility was observed for some austenitic stainless steels even after 250 h exposure. The contribution of $S-CO_2$ environment on such changes was analyzed based on the characterization of the surface oxide and carburization of the materials in which 316H and 800H showed different oxidation behaviors.

• Fire Science and Engineering
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• v.17 no.3
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• pp.31-44
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• 2003

In the Local Autonomy Law, we regard the fire-fighting service as inherent service for the local government. However, if we look into the course of the charge of fire-fighting service, after the transfer of this from the police service, or the state, to the local service in 1991, this is now taking a firm hold as service of the local government. what we call the local services includes the business about the welfare of the residents and that of taking in charge of the resident properties, proclaimed in the Constitution. That is to say, the basic purpose of the local autonomy is to make the residents feel the most convenient and safe, and this is the mission of the present-day local autonomy. Looking from this point of view, if we consider that the ultimate purpose of fire-fighting is promoting the welfare of the residents by preventing and putting out fires and, in the time of emergency, carrying out rescue and relief operations, and furthermore, maintaining the safety and order of a society, until present time the benefits of fire-fighting business were mainly available to the residents of the cities. In order to break from these thoughts, according to the result of comparing and analyzing the metropolitan city, surrounding rural areas, middle and small cities and typical rural areas, the rural areas are urgently demanding fire-fighting service, so it is being proved that it is necessary to install the offices in these areas. Therefore, the installation of the fire-fighting offices in the counties that are the basic units of the primary local autonomy and are rural areas should be expanded as part of the welfare administration.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.90-105
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• 2004

Machines for crack sealing automation have been continually developed since the early 1990's because of the effectiveness of crack sealing that would be able to improve safety, quality and productivity. It has been considered challenging problem to detect crack network in pavement which includes noise (oil marks, skid marks, previously sealed cracks and inherent noise). Moreover, it is required to develop crack network mapping and modeling algorithm in order to accurately inject sealant along to the middle of cut crack network. The primary objective of this study is to propose machine vision algorithms (digital image processing algorithm and path planning algorithm) for fully automated pavement crack sealing. It is anticipated that the effective use of the proposed machine vision algorithms would be able to reduce error rate in image processing for detecting, mapping and modeling crack network as well as improving quality and productivity compared to existing vision algorithms.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.373-380
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• 2017

Operational errors caused by human factors, which is the major cause of marine accidents, include lack of knowledge, misunderstanding knowledge, and inadequate procedures. Recently, the type of propulsion mounted on KCG cutters has been diversified. In particular, the water jet propulsion unit, which was mainly installed in small boats, have been gradually expanded to medium and large size Coast Guard cutters, reaching 50% of the total. Axes types are divided into 2 to 4, and the bucket types are divided into Double Reverse Bucket(DRB) and Single Reverse Bucket(SRB); in these, the backward and steering control methods are completely different. Diversification of these operating systems can increase factors causing human error by the ships' operators. However, there is a lack of research on the maneuvering methods, considering the inherent active characteristics of each type of water jet. In this paper, we analyze the sideway method suitable for the condition of Coast Guard Exclusive wharf without assistance, based on the astern performance of each type. Then, a ship handling simulator was used for the experiment; they compared and verified through interviews of captains.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.1-9
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• 2003

A Multi-distinction Equipment Screening Algorithm (MESA) is proposed. It selectively integrates Dow's F&EI as its process hazard index technique and ESA (Equipment Screening Algorithm) as qualitative hazard classification technique, and retrieves a detailed list of hazardous equipments with the total hazard indices of those equipments. The inherent expert system, which includes the accident scenarios of the equipments and processes and experts' views of them, narrows further down the list of hazardous equipments and recommends only the most notable candidates. Through the case study of distinguishing the hazardous ranking of the equipments of the LPG underground storage process, using the expert system or not, the applicability of MESA has been validated. Taking the characteristics of the process equipments with hazardous ranking in the point of process intrinsic safety, this proposed algorithm would contribute to providing engineers or managers with information on constructing safely devices and mitigation devices and on scheduling emergency response planning.