• Journal of the Economic Geographical Society of Korea
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• v.19 no.1
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• pp.33-50
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• 2016

Hannam-dong, which lies at the eastern part of Yongsan-gu in metropolitan Seoul has been known as one of the affluent area, but actually it is divided into different sub-areas including poor ones. Although it used to be a quiet residential neighborhood, be they rich or poor, some streets (gil) have become the places of creative economy since the late 2000s. The place-making of Hannam-dong is accompanied by taking-place of different creative classes in different sub-areas, and there have emerged contestation, negotiation and clash among them at the contact zone. While the big companies such as Samsung explores their own version of cultural/creative entrepreneurialism in one sub-area, the actors that can be dubbed as 'creative small producer' and/or 'creative underlass' produce Hangangjin-gil and Usadan-gil as artistic-cum-economic communities by deploying cultural capital. All in all, Hannam-dong is an interesting case that different types of gentrifications are produced by different actors in different sub-areas, which results in producing another kind of 'community of strangers' where different (creative) classes share a physical location, but do not have lasting social interactions and communicative networks.

• 한국해양학회지
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• v.26 no.1
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• pp.24-37
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• 1991

Marine benthic diatoms and environmental factors were studied at 60 sites on the Mangyung-Dongjin tidal flat of the west coast of Korea. Sediment samples were taken quantitatively from the upper 5 mm layer to obtain a representative estimate of the epipelic and epipsammic cell concentration. Surface sediments taken simultaneously with the quantitative diatom samples were analysed for the grain size. Exposure duration of study sites were calculated by the tide data recorded at Kunsan Outer-Harbour. Coarse sediments dominated mainly on the offshore coastal and lower tidal flat, whereas fine sediments occurred on inner and higher tidal flat. Total 371 diatom taxa were collected and the genera represented by a great number were Navicula and Nizschia. The 16 abundant species occupying more than 1% of total cell number are of the following: Paralia sulcata, Navicula sp. 1, Navicula arenaria, Cymatosira belgica, Amplora holsatica, Amphora coffeaeformis, Achnanthes hauckiana, Rhaphoneis amphiceros, Thalassionema nitzschioides. Navicula sp. 2, Dimeregramma minor, Amphora sp. 1, Cyclotella atomus, C, striata, Nitzschia kuetzingiana, Stephanodiscus sp. 1. The distribution pattern of these dominant species are described in relation to the habitat condition. Most of these species showed high densities in fine sediments. However, they occurred even silty sand and sandy sediments in low abundance. The epipsammic forms belonging to the Araphidineae and Monoraphidineae were restricted on the lower tidal flat. The typical species found in coarse sediments were: Cocconeis sp. 1, Opephora martyi, Amphora sabyii, Dimeregramma minor var. nana, Fragilaria virescens var. oblongella, F. virescens, Cocconeis grata. The higher tidal flat consisting of fine sediments showed relatively higher cell numbers than the lower tidal flat. River mouth region was the highest in abundance.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.56-63
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• 1997

This paper presents a hybrid network model(HY-PIPENET) implementing a minimum cost spanning tree(MCST) network algorithm to be able to determine optimum path and constrained derivative(CD) method to select optimum Pipe diameter. The HY-PIPENET has been validated with the published data of 6-node/7-pipe network. Networking system and also this system has been optimized with MCST-CD method. As a result, it was found that the gas can be sufficiently supplied at the lower pressure with the smaller diameters of pipe compared to the original system in 6-node/7-pipe network. Hence, the construction cost was reduced about $40\%$ in the optimized system. The hybrid networking model has been also applied to a complicated domestic gas pipeline network in metropolitan area, Korea. In this simulation, parametric study was peformed to understand the role of each individual parameter such as source pressure, flow rate, and pipe diameter on the optimized network. From the results of these simulations, we have proposed the optimized network as tree-type structure with optimum pipe diameter and source pressure in metropolitan area, Korea, however, this proposed system does not consider the environmental problems or safety concerns.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.96-103
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• 2018

An analysis using a statistical method is generally used to determine the effective temperature based on the temperature design load of a bridge. In this study, the effective temperature was calculated by building an artificial neural network (ANN) capable of improving the statistical method. A Steel box girder bridge specimen was made with a width of 2.0 m, height of 2.0 m, and length of 3.0 m and 0.2 m the upper slab. Twenty one temperature gauges were attached to measure the temperature between 2014 and 2016 for three years. An ANN was learned using the data measured from 2014~2015 and the results were compared with the Euro codes. The error rate between the Euro code and statistical analysis values was analyzed to be 4.1 % for the total measurement point. The ANN was verified and the effective bridge temperatures were calculated using the temperature data measured in 2016. The results revealed an approximate 3.97 % difference from the statistical analysis values. This degree of error is considered to be acceptable in terms of engineering for the analysis of an ANN. An ANN can easily predict the effective temperature of a bridge by knowing the input values of the region's highest temperature, bridge type, and upper asphalt thickness when designing the bridge's temperature loads.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.17-30
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• 2002

Incident duration prediction is one of the most important steps of the overall incident management process. An accurate and reliable estimate of the incident duration can be the main difference between an effective incident management operation and an unacceptable one since, without the knowledge of such time durations, traffic impact can not be estimated or calculated. This research presents several multiple linear regression models for incident duration prediction using data consisting of 384 incident cases. The main source of various incident cases was the Traffic Incident Reports filled out by the Motorist Assistant Units of the Korea Highway Corporation. The models were proposed separately according to the time of day(daytime vs. nighttime) and the fatality/injury incurred (fatality/injury vs. property damage only). Two models using an integrated dataset, one with an intercept and the other without it, were also calibrated and proposed for the generality of model application. Some findings are as follows ; ?Variables such as vehicle turnover, load spills, the number of heavy vehicles involved and the number of blocked lanes were found to significantly affect incident duration times. ?Models, however, tend to overestimate the duration times when a dummy variable, load spill, is used. It was simply because several of load spill incidents had excessively long clearance times. The precision was improved when load spills were further categorized into "small spills" and "large spills" based on the size of vehicles involved. ?Variables such as the number of vehicles involved and the number of blocked lanes found not significant when a regression model was calibrated with an intercept. whereas excluding the intercept from the model structure signifies those variables in a statistical sense.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.126-127
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• 2003

원예산물의 밀도나 비중은 내부성분, 숙도, 내부붕괴(internal breakdown)와 같은 생리장해에 큰 영향을 받기 때문에, 밀도를 측정함으로써 내부품질에 대한 간접적인 판정이 가능하다고 보고되고 있다. 이 연구는 수박의 밀도와 당도와의 상관관계를 구명하고자 수행하였으며, 이를 위해 밀도의 실시간 계측시스템을 개발하였다. 현재 농산물의 밀도를 어느 정도 측정 정밀도를 유지하면서도 신속하게 측정할 수 있는 방법은 부력법(platform scale method)이다. 이 방법은 일정 크기의 용기에 물을 가득 채운 후 대상물을 담가 배제된 물의 무게를 측정하여 밀도를 환산한다. 그러나 매번 측정할 때마다 물을 보충하고, 물을 계량해야하는 등 전처리과정이 복잡하고, 1회 측정하는데 3~5분 정도가 소요되는 단점이 있고, 또한 인력 측정시 반복간 오차가 클 것으로 예상된다. 따라서 이 연구에서는 이 같은 계측상의 번거로움을 해소하고 동시에 신속하고 반복간 측정정밀도를 높일 수 있도록 수박 밀도 실시간 계측시스템을 설계 제작하였다. 시스템은 투명아크릴 수조($\Phi$400$\times$500), 로드셀, 프레임, 채반, 전기모터, 제어장치 및 컴퓨터로 구성하였다. 밀도 계측은 인장형 로드셀(CAS SB-20L, Max. 20kg)을 사용하여 대기중에서와 수박을 완전히 물에 잠기도록 한 후 무게를 각각 측정하여 밀도를 환산하였다. 밀도 계측시스템에 이용한 AD변환기의 분해능은 12bit이고, 수박의 무게 측정범위를 4~10kg로 가정할 때 20kg 로드셀의 1 digit(1bit)로 발생되는 오차는 0.09~0.24%FS 이었고, 따라서 이 시스템의 밀도 해상도는 0.001g/㎤이하였다. 시스템 평가를 위해 탄력이 좋은 고무풍선에 수박 크기 정도로 물을 채워 고정채반에 넣고 밀도를 측정한 결과 1.002g/㎤을 나타냈다. 즉 물의 이론밀도인 1g/㎤에 근접한 값을 보여 정확한 밀도 계측이 가능한 것으로 판단되었다. 또한 밀도 계측시스템의 측정 반복간 정밀도를 파악하기 위해 수박 6개를 임으로 선정하여 3반복 측정 시험한 결과, 측정표준편차가 0.001~0.004g/㎤로 해상도보다는 다소 높았으나 대체로 양호한 결과를 나타냈다. 수박 35개를 이용하여 개발 계측시스템과 사람이 직접 부력법으로 밀도를 측정 비교한 결과, 계측시스템에 의해 측정된 수박 밀도가 사람이 측정했을 때 보다 낮게 측정되었다. 수박의 외관인자(무게, 길이, 직경, 체적), 밀도와 당도의 상관관계 구명시험을 위해 원예연구소 시험포장에서 재배된 삼복꿀수박 총 74개를 공시재료로 하였고, 시험은 출수일별로 10~14개씩 수확하여 외관인자, 밀도, 당도를 각각 측정하고, 이들 인자들간의 상관관계를 구명하였다. 외관인자들간에는 높은 상관관계를 보였으나, 외관인자들과 밀도, 외관인자들과 당도, 밀도와 당도와는 매우 낮은 상관관계를 나타냈다.

• Journal of the Korean Geotechnical Society
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• v.29 no.6
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• pp.53-62
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• 2013

A 5-20 cm thick shocrete has been routinely constructed for NATM tunneling method to stabilize and confine the excavated rock of tunnel construction site. A $40kg/m^3$ of steel fibers are usually mixed into such shotcrete but these steel fibers may not be evenly distributed depending on shotcrete machines, mixing ratios and excavated rock conditions. In this study, square column shotcrete-mimicked concrete specimens of $15cm{\times}15cm{\times}55cm$ were prepared with 5 equal layers and 5 or 20% cement ratio. The specimens were prepared with different reinforced-patterns: non-reinforced, middle layer-reinforced, 1, 3, and 5 layers-reinforced, or all layers reinforced. The specimens were air-cured for 7 days and tested for flexural strength. The influence of steel-fiber distribution on flexural strength and toughness of shotcrete-mimicked concrete specimens was investigated. In the case of a specimen with cement ratio of 20%, a flexural strength increased as a number of fiber-reinforced layer increased. The flexural strength of one-layer reinforced specimen showed 20% less than that of evenly fiber-distributed specimen. On the other hand, a specimen with cement ratio of 5% decreased as the number of fiber-reinforced layers increased. A toughness index increased as the number of fiber-reinforced layers increased, regardless of cement ratios. The toughness index of evenly fiber-distributed specimen showed 2-3 times as large as that of one-layer reinforced specimen.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.668-673
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• 2005

To collect or transfer samples of gaseous pollutants, various types of tubing are used. Hence, to analyze the uncertainties associated with the use of tubings, a series of comparative test were designed and conducted using the RSC standards with different concentration ranges. For the purpose of this study, we prepared tubings made of six different types of material which include: [1] silco-steel (S1), [2] stainless steel (S2), [3] silicone (S3), [4] PTFE Teflon (T1), [5] tygon (T2), and [6] brass (B). The patterns of RSC loss on to tubing walls, when compared on the basis of the least reactive material S1, exhibited that the extent of RSC loss varied dynamically. It was found that Teflon is highly stable. However, other materials tend to exhibit contrasting patterns of loss. S2 and B show significant loss of light RSC $(H_2S\;and\;CH_3SH)$, while S3 and T2 experience notable loss of heavy RSC (DMS and DMDS).

• Journal of Korea Port Economic Association
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• v.33 no.4
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• pp.73-82
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• 2017

Korea is the fifth largest producer of automobiles in the world, and this industry accounts for the highest portion of the entire manufacturing industry. It is an especially important industry occupying second place in the top 10 export items in Korea. Korea exports about 3 million units of cars produced in the country and abroad, based on new cars and excluding second hand cars. Japan, along with Korea, represents a high portion of the global automobile industry, and it exports more than 4 million cars to the rest of the world. In particular, both Korea and Japan export automobile and used cars produced within the country, almost all of them by PCC(Pure Car Carrier) or PCTC(Pure Car Truck Carrier). Therefore, automobile export ports are located near automobile factories, and are being used in export to foreign countries. However, there are inefficient problems, such as poor port facilities, yard space shortage for loading and unloading operations and lack of proficiency of cargo handling companies. As a result, there are delays in cargo operations, or ships waiting have occurred. Therefore, the purpose of this study is to measure and compare the efficiency of automobile export ports in Korea and Japan. To measure the efficiency of automobile export port, we used CRS and VRS models from DEA. The input and output parameters were set as length of quay, yard area and throughput of cars, and DMUs are 25 ports for evaluating the efficiency. As a result of the efficiency measurements, two Korean ports (Gwangyang and Ulsan) and three Japanes ports (Kanda, Omaezaki, Kanmon-Shimonoseki) showed high efficiency in both models. These results can be used to establish strategies for enhancing efficiency and competitiveness of automobile export ports in Korea and Japan.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.106-112
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• 2012

In order to understand the growth and ecophy -siological response of ginseng to global warming condition, we cultivated one and two year ginseng seedlings in control (ambient $CO_2$ + ambient temperature) and global warming treatment (elevated $CO_2$ + elevated temperature) from March 2010 to July 2011. Shoot appearance and initiation of flowering were advanced by 3-4 days in global warming treatment than in control. However, timing of fruit setting and seed ripeness was similar in both control and global warming treatment. Shoot length was longer in global warming treatment than in control, and also the number of leaves was much in global warming treatment. Fresh root weight was not different between control and global warming treatment. Photosynthetic rate was higher in global warming treatment than at control. Photosynthetic rate and transpiration rate were higher in two year seedlings than in one year seedlings at control, but was not different between seedling age of ginseng in global warming treatment. Water use efficiency was higher in one year seedlings than two year seedlings at control and global warming treatment. These results demonstrated that Korean ginseng more or less positively responds to global warming situation.