• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.2
• /
• pp.247-252
• /
• 2015

The majority of electric power in the domestic manned islands with off-grid power system is supplied by the diesel generators. However, in the case of off-grid islands the fuel cost is more expensive to inland areas and difficult to transport them to islands. So the development of renewable energy system using natural resource have been recently introduced. But renewable energy that depend on the natural environment, it is necessary to organized the hybrid system with existing diesel engine because the energy is difficult to maintain stable electric power. This paper presents the results of a feasibility study of hybrid system with energy storage system such as wind, solar, battery and diesel engine. The study included off-grid island as the Seogeochado islands located in Jeolanamdo Province. And, the paper proposed a optimal capacity of hybrid system configuration to maintain carbon free with minimum investment cost. the analysis of economic adaptability performed by HOMER program.

• Journal of the Korean Institute of Gas
• /
• v.26 no.6
• /
• pp.52-58
• /
• 2022

According to the government's roadmap for revitalizing the hydrogen economy, various industries carry out projects using liquefied hydrogen as an energy source. However, safety standards necessary for operational demonstration projects are not prepared in Korea, thus, it is necessary to prepare safety standards as soon as possible. Therefore, in order to secure the safety of liquefied hydrogen instrumentation and handling facilities, it is necessary to prepare safety standards that comprehensively consider the risk of liquefied hydrogen. This study aims to prioritize safety standard items using ETA, FMEA, and AHP, which are risk assessment techniques, to present the feasibility of selecting safety standard items.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.201-208
• /
• 2011

When designing a river, it is important to select the appropriate bank revetment methods, but there are no specific guidelines until now. Accordingly, it is important to prevent over-budgeting by deciding the suitability of the adopted bank revetment methods when designing a river. In this study, an assessment method was developed to assess the suitability of the adopted bank revetment methods when designing a river. By adopting this method to eight rivers, its validity was examined. Analytic Hierarchy Process (AHP) was used for the assessment, along with suitability index (SI) of the adopted bank revetment methods when designing a river. In order to select the best bank revetment methods, all environmental variables of the selected location have to be considered. Accordingly, to assess the designed bank revetment methods, all variables of the selected location have to be considered. The assessing items include hydraulic stability, environmental-ecological feasibility, economy, and amenity of the bank revetment. Each item includes four to five sub-items, and each sub-items reflect survey results on the locations. The assessment method was adopted and assessed for eight rivers, and bank revetments was designed to determine the SI. The result of this study is considered to be appropriate when assessing an eco-friendly bank revetment methods, and inappropriate designed bank revetments will guide future planners for selecting the most appropriate construction method.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.4
• /
• pp.605-615
• /
• 2016

It is difficult to form a rational strut-tie model that represents a true load transfer mechanism of structural concrete with disturbed stressed region(s). To overcome the difficulty and handle numerous load cases with just one strut-tie model, a two-dimensional grid strut-tie model method was proposed previously. However, the validity of the method was not fully examined, although the incorporated basic concepts and new methods regarding the effective strength of concrete strut, load carrying capacity of struts and ties, and geometrical compatibility of grid strut-tie model were explained in detail. In this study, for accurate strength analysis and reliable design of reinforced concrete deep beams, the appropriateness of the two-dimensional grid strut-tie model method is verified. For this, the failure strength of 237 reinforced concrete deep beams, tested to shear failure, is predicted by the two-dimensional grid strut-tie model method, and the results are compared with those obtained by the sectional shear design methods and conventional strut-tie model methods of current design codes.

• Economic and Environmental Geology
• /
• v.41 no.3
• /
• pp.287-297
• /
• 2008

In order to estimate the preliminary development feasibility according to the commodity, the content of 8 strategic metallic commoditites(Pb, Zn, Cu, Fe, Mo, W, Au, U) in 68 ore specimens obtained from 34 metallic mines within the Taebaegsan-Hwanggangri mineralized zone were analyzed. Analytical results are as follows. The ore specimen of Sangdong mine contained 23% copper(cut-off grade=0.7%) and those of Cheongil and Samhwanghak mines contained average 5% zinc(cut-off grade=2.0%). Especially, the detailed investigation on the above-mentioned mines is required. And, in case of molybdenum(cut-off grade=0.02%) content in Yeonhwa No. 2(0.04%) and Hong-cheon mine(0.02%), and lead(cut-off grade=0.58%) content in Wongasa mine(0.70%), and gold(cut-off grade=10ppm) content in Dongmyoung(279ppm) and Samhwanghak mine(251ppm), it is required to elastically carry out the revaluation on reopening of mines in terms of the international metal price. On the other hand, in case of uranium, iron and tungsten, it is thought that there are no mines with the development potential value in this study.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.4
• /
• pp.105-117
• /
• 2010

The topographical depressions in urban areas, the lack in drainage capability, sewage backward flow, road drainage, etc. cause internal inundation, and the increase in rainfall resulting from recent climate change, the rapid urbanization accompanied by economic development and population growth, and the increase in an impervious area in urban areas deteriorate the risk of internal inundation in the urban areas. In this study, the vulnerability of internal inundation in urban areas is analyzed and SWMM model is applied into Oncheoncheon watershed, which represents urban river of Busan, as a target basin. Based on the results, the representative storm sewers in individual sub-catchments is selected and the risk of vulnerability to internal inundation due to rainfall in urban streams is analyzed. In order to analyze the risk and vulnerability of internal inundation, capacity is applied as an index indicating the volume of a storm sewer in the SWMM model, and the risk of internal inundation is into 4 steps. For the analysis on the risk of internal inundation, simulation results by using a SMMM model are compared with the actual inundation areas resulting from localized heavy rain on July 7, 2009 at Busan and comparison results are analyzed to prove the validity of the designed model. Accordingly, probabilistic rainfall at Busan was input to the model for each frequency (10, 20, 50, 100 years) and duration (6, 12, 18, 24hr) at Busan. In this study, it suggests that the findings can be used to preliminarily alarm the possibility of internal inundation and selecting the vulnerable zones in urban areas.

• Korean Journal of Construction Engineering and Management
• /
• v.13 no.4
• /
• pp.48-59
• /
• 2012

Gangform, compared to the traditional forms, is a systemized form which can reduce construction duration and cost by the advantage of using it repeatedly. However, transportation and climbing process of the Gangform is highly dependant on the performance of tower crane. Gangform climbing process takes one day out of six to seven days of a structural work cycle. Tower cranes can not be used in other lifting works when they lift the Gangform during the structural work cycle, causing the delay in the construction project. Numerous efforts and researches have been done in domestic and international industry to solve such limitations of Gangform climbing process. Especially, "A Study on the Development of Automatic Gangform Climbing System for Apartment Housing Construction"has suggested a conceptual model which can climb the Gangform system without a tower crane. In this paper, the technical and economical feasibilities of previously proposed Automatic Gangform climbing system are examined by evaluating its structural stability and lifting load reduction effect.

• Journal of Korean Society of Transportation
• /
• v.21 no.4
• /
• pp.133-144
• /
• 2003

The current procedure of estimating accident reduction benefit shows fixed accident rates for each level of roads without considering the various characteristics of roadway geometries, and traffics. In this study, in order to solve the problems mentioned in the above, models were developed considering the characteristics of roadway alignments and traffic characteristics. The developed models can be used to estimate the accident rates on new or improved roads, In this study, only urban highways were included as a beginning stage. First of all. factors influencing accident rates were selected. Those factors such as traffic volumes. number of signalized intersections, the number of connecting roads, number of pedestrian traffic signals, existence of median barrier, and the number of road lane are also selected based upon the obtainability at the planning stage of roads. The relationship between the selected factors and accident rates shows strong correlation statistically. In this study, roads were classified into 4 groups based on number of lanes, level of roads and the existence of median barriers. The regression analysis had been performed for each group with actual data associated with traffic, roads. and accidents. The developed regression models were verified with another data set. In this study, in order to develop the proposed models, only data on a limited area were used. In order to represent whole area of the country with the developed models. the models should be re-analyzed with vast data.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.5
• /
• pp.455-461
• /
• 2017

The Hebei Spirit oil spill incident occurred in December 7, 2007 and caused approximately $12,547k{\ell}$ of crude oil spillage along 370km off the west coast of Korea. Due to the astronomical and irrecoverable damage to the marine ecosystems and the overall living standards of the residents, the oil spill incident has been notoriously named as the "worst oil spill incident" occurred in Korea. Nevertheless, though almost a decade has passed since the tragic incident in Korea, it appears that compensation and recovery efforts seem not close to satisfaction and the local residents are still struggling with various negative impacts incurred by the incident because of critical cleavage among the interests of the relevant parties to the incident. In this paper, the analysis of Hebei Spirit oil spill incident regarding two aspects was carried out; First, meticulously analyze the practical and statistical data of the incident to precisely examine the fundamental causes for its occurrence to further prevent the reoccurrence of such disastrous incident; and the second, comprehensively inspect reasons for the protracted and inefficient damage recovery and victim-oriented compensation. To be specific, this study observed the levels of compensation against damages from the incident, and the adequacy of it in terms of ultimately and inclusively addressing financial, social and ecological aspects based primarily upon the legal verdicts, and statistical and empirical surveys.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.145-150
• /
• 2015

Needs about safety of residents are important in urbanized society, elderly and small-size family. People are looking for safety information system and device of CPTED. That is, Needs and Installations of CCTV increased steadily. But, scientific analysis about validity, systematic plan and location of security CCTV is nonexistent. It is simply put these devised in more demanded areas. It has limits to look for safety of residents by increasing density of CCTVs. One of the characteristics of crime is clustering and stong interconnectivity. So, exploratory spatial data of crime is geo-coded using 2 years data and carried out cluster analysis and space statistical analysis through GIS space analysis by dividing 18 variables into social economy, urban space, crime prevention facility and crime occurrence index. The result of analysis shows cluster of 5 major crimes, theft, violence and sexual violence by Nearest Neighbor distance analysis and Ripley's K function. It also shows strong crime interconnectivity through criminal correlation analysis. In case of finding criminal cluster, you can find criminal hotspot. So, in this study I found concept of hotspot and considered technique about selection of hotspot. And then, selected hotspot about 5 major crimes, theft, violence and sexual violence through Nearest Neighbor Hierarchical Spatial Clustering.