• Title/Summary/Keyword: Large Construction Projects

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A Study on Strength and Durability Characteristics of Cemented Weathered Mudstone (풍화 이암 고결토의 강도 및 내구성 특성에 관한 연구)

  • Kim, Seong-Heon;Moon, Hong-Duk;Park, Sung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.35 no.10
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    • pp.33-45
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    • 2019
  • In this study, in order to recycle a large amount of rocks and weathered mudstones produced by civil engineering projects such as railways and highways, as materials for roadbeds or embankment materials, circumferential specimens with a diameter of 5 cm and a height of 10 cm were made. A mudstone that weathered rapidly during rainfall was collected from Pohang construction sites. The weathered mudstone passed through a 2 mm sieve. It was prepared with the cement ratio, the sand ratio, curing condition and curing days. Three specimens were prepared according to each condition and then the unconfined compressive test, durability test and SEM analysis were performed to evaluate the engineering properties of the cemented soil. In the case of 28 days cured specimen, the strength of under-water cured specimens was 32-55% and the durability index was about 15% higher than air cured specimens. In addition, when the CR increased from 8% to 16%, the unconfined compressive strength (UCS) of pure mudstone cemented soil under water increased by about 1.6 times and the durability index increased by about 1.9 times. When the SR increased from 0% to 50%, the UCS of the specimen with SR = 10% was slightly less than or equal to specimen with SR = 0%. Then, as the SR became 30-50%, the UCS increased up to 51%. Unlike the UCS, the durability index increased continuously as the SR increased. As a result of SEM analysis, when SR was 50% rather than SR = 0%, the contact between sand particles increased and they were connected to each other. Such contact between these particles resulted in the increase of strength.

Design and Implementation of Modbus Communications for Smart Factory PLC Data Collection (스마트팩토리 PLC 데이터 수집을 위한 Modbus 통신 설계 및 구현)

  • Han, Jin-Seok;Yoo, Jae-Soo
    • The Journal of the Korea Contents Association
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    • v.21 no.4
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    • pp.77-87
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    • 2021
  • Smart Factory refers to a factory that can be controlled by itself with an intelligent factory that improves productivity, quality and customer satisfaction by combining the entire process of manufacturing and production with digital automation solutions. The manufacturing industry around the world is rapidly changing, with Germany, Europe, and the United States at the center. In order to cope with such changes, the Korean government is also implementing a policy to spread the supply of smart factories for small and medium-sized companies, and related ministries and agencies such as the Ministry of Commerce, Industry and Energy, the Ministry of SMEs and Venture Business, the Korea Institute of Technology and Information Promotion, and local technoparks, as well as large companies such as Samsung, SK and LG are actively investing in smart manufacturing projects to support smart factories[1]. Factory Automation (FA) construction has many issues regarding the connection of heterogeneous equipment. The most difficult aspect of configuring various communications from various equipment is the reason. Although it may not be known if there are standards or products made up of the same company, it is not easy to build equipment that is old, up-to-date, and different use environments through a series of communications. To solve this problem, we would like to propose a method of communication using Modbus, one of FieldBus, which is one of the many industrial devices of PLC, a representative facility control system, and is used as a communication standard.

A Study on Policies for Conservation Measures Based on the Status and Issues of Conserved Remains (보존유적 현황과 문제 인식을 통한 보존조치 제도 연구)

  • So, Jaeyun
    • Korean Journal of Heritage: History & Science
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    • v.53 no.3
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    • pp.110-127
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    • 2020
  • The term "conserved remains" refers to cultural remains that are preserved in accordance with the valuation of buried cultural properties when important remains are recognized in rescue excavations during construction work. South Korea's rapid economic growth and ensuing land development over the past few decades compelled a sharp increase in the number of rescue excavation cases, and, naturally, of conserved remains. Today, an increasingly large number of conserved remains have raised issues, including those concerning land expropriation as well as the management and utilization of such remains, but no clear solutions have been proposed. This study attempts to propose plans for improvement based mainly on the recognition of institutional issues rather than technical issues related to the conservation of cultural remains. This is because the identification and review of institutional deficiencies must be prioritized in order to efficiently manage conserved remains with limited resources and manpower. Among many possible proposals to demand improvement of conservation policies, one that must first be examined under the current system is the rapid transition, or review thereof, of "conserved remains" to "designated cultural properties." Unlike designated cultural properties, conserved remains are merely a temporary means of conservation, because they lack regulations for follow-ups subsequent to preliminary measures. Naturally, deferring the definition of relics as "conserved remains" for extended periods causes numerous problems. Measures to resolve such problems may include establishing a legal system to manage conserved remains at a level similar to designated cultural properties or seeking ways to improve management under the current system. This study focuses on areas where institutional improvement for conserved remains is possible by methods other than through the rapid transition to designated cultural properties and presents several proposals. Currently, conservation measures are divided into three categories: on-site conservation, relocation conservation, and record conservation. This study reclassifies these categories from three into four categories. On-site conservation includes only two categories: conserved remains and the newly-proposed soil-covered remains. Two remaining categories, the relocation conservation remains and the record conservation remains, are presented as classifications in which development projects are possible, and they are presented as alternative conservation types that contrast with on-site conservation. Unlike conserved remains, soil-covered conservation presented as a new category in which development projects are possible.

A Comprehensive Review of Geological CO2 Sequestration in Basalt Formations (현무암 CO2 지중저장 해외 연구 사례 조사 및 타당성 분석)

  • Hyunjeong Jeon;Hyung Chul Shin;Tae Kwon Yun;Weon Shik Han;Jaehoon Jeong;Jaehwii Gwag
    • Economic and Environmental Geology
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    • v.56 no.3
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    • pp.311-330
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    • 2023
  • Development of Carbon Capture and Storage (CCS) technique is becoming increasingly important as a method to mitigate the strengthening effects of global warming, generated from the unprecedented increase in released anthropogenic CO2. In the recent years, the characteristics of basaltic rocks (i.e., large volume, high reactivity and surplus of cation components) have been recognized to be potentially favorable in facilitation of CCS; based on this, research on utilization of basaltic formations for underground CO2 storage is currently ongoing in various fields. This study investigated the feasibility of underground storage of CO2 in basalt, based on the examination of the CO2 storage mechanisms in subsurface, assessment of basalt characteristics, and review of the global research on basaltic CO2 storage. The global research examined were classified into experimental/modeling/field demonstration, based on the methods utilized. Experimental conditions used in research demonstrated temperatures ranging from 20 to 250 ℃, pressure ranging from 0.1 to 30 MPa, and the rock-fluid reaction time ranging from several hours to four years. Modeling research on basalt involved construction of models similar to the potential storage sites, with examination of changes in fluid dynamics and geochemical factors before and after CO2-fluid injection. The investigation demonstrated that basalt has large potential for CO2 storage, along with capacity for rapid mineralization reactions; these factors lessens the environmental constraints (i.e., temperature, pressure, and geological structures) generally required for CO2 storage. The success of major field demonstration projects, the CarbFix project and the Wallula project, indicate that basalt is promising geological formation to facilitate CCS. However, usage of basalt as storage formation requires additional conditions which must be carefully considered - mineralization mechanism can vary significantly depending on factors such as the basalt composition and injection zone properties: for instance, precipitation of carbonate and silicate minerals can reduce the injectivity into the formation. In addition, there is a risk of polluting the subsurface environment due to the combination of pressure increase and induced rock-CO2-fluid reactions upon injection. As dissolution of CO2 into fluids is required prior to injection, monitoring techniques different from conventional methods are needed. Hence, in order to facilitate efficient and stable underground storage of CO2 in basalt, it is necessary to select a suitable storage formation, accumulate various database of the field, and conduct systematic research utilizing experiments/modeling/field studies to develop comprehensive understanding of the potential storage site.

Patterns of Snake Roadkills on the Roads in the Northeast Region of South Korea (남한 동북부지역 도로에서 뱀류 로드킬의 양상)

  • Park, Daesik;Jeong, Soo-Min;Kim, Seung-Kyu;Ra, Nam-Yong;Lee, Jeong-Hyun;Kim, Ja-Kyeong;Kim, Il-Hun;Kim, Dae-In;Kim, Seok-Bum
    • Korean Journal of Environment and Ecology
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    • v.31 no.1
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    • pp.42-53
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    • 2017
  • One of the negative ecological effects following road construction is roadkill; animals die on the roads after being struck by vehicles. Roadkills have been a major concern in South Korea due to the large mountain areas in the country and have been mentioned as a causal factor for the decline in wildlife. Although snake roadkills frequently occur, as with mammals, birds, and amphibians, there are not many related studies done on snake roadkills. In this study, we determined snake roadkill patterns in the northeast part of South Korea including most of the Gangwon-do areas and parts of Gyeonggi-do, Chungcheongbuk-do, and Gyeongsangbuk-do by analyzing the snake roadkills found between May 2007 and Aug 2012. We identified a total of 155 roadkilled snakes from 10 different species. Red-sided water snake (Rhabdophis tigrinus), Red-tongue viper snake (Gloydius ussuriensis), Cat snake (Elaphe dione), Red-banded snake (Dinodon rufozonatus), and Viper snake (Gloydius brevicaudus) accounted for more than 90% of the total cases. It was found that more active forager snakes were killed than sit-and-wait foragers, more male snakes were killed than female snakes, and more adult snakes were killed than subadult snakes. The snake roadkill frequency was the highest in September between the altitudes of 200 and 400 m, and on roads between either a mountain and a body of water or between a mountain and a crop field. Our results are expected to enhance the understanding of snake roadkills in general and to determine the areas, specific sites and species for planning projects for snake roadkill reduction in the northeast of South Korea.

Analysis of Urban Heat Island (UHI) Alleviating Effect of Urban Parks and Green Space in Seoul Using Deep Neural Network (DNN) Model (심층신경망 모형을 이용한 서울시 도시공원 및 녹지공간의 열섬저감효과 분석)

  • Kim, Byeong-chan;Kang, Jae-woo;Park, Chan;Kim, Hyun-jin
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.4
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    • pp.19-28
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    • 2020
  • The Urban Heat Island (UHI) Effect has intensified due to urbanization and heat management at the urban level is treated as an important issue. Green space improvement projects and environmental policies are being implemented as a way to alleviate Urban Heat Islands. Several studies have been conducted to analyze the correlation between urban green areas and heat with linear regression models. However, linear regression models have limitations explaining the correlation between heat and the multitude of variables as heat is a result of a combination of non-linear factors. This study evaluated the Heat Island alleviating effects in Seoul during the summer by using a deep neural network model methodology, which has strengths in areas where it is difficult to analyze data with existing statistical analysis methods due to variable factors and a large amount of data. Wide-area data was acquired using Landsat 8. Seoul was divided into a grid (30m × 30m) and the heat island reduction variables were enter in each grid space to create a data structure that is needed for the construction of a deep neural network using ArcGIS 10.7 and Python3.7 with Keras. This deep neural network was used to analyze the correlation between land surface temperature and the variables. We confirmed that the deep neural network model has high explanatory accuracy. It was found that the cooling effect by NDVI was the greatest, and cooling effects due to the park size and green space proximity were also shown. Previous studies showed that the cooling effects related to park size was 2℃-3℃, and the proximity effect was found to lower the temperature 0.3℃-2.3℃. There is a possibility of overestimation of the results of previous studies. The results of this study can provide objective information for the justification and more effective formation of new urban green areas to alleviate the Urban Heat Island phenomenon in the future.

A study on the management of drawings of Metropolitan Rapid Transit (도시철도 도면 관리에 관한 연구 -서울시 도시철도공사를 중심으로-)

  • Kim, Miyon
    • The Korean Journal of Archival Studies
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    • no.11
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    • pp.181-214
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    • 2005
  • Metropolitan rapid transit system plays an essential role in the public transportation system of any large city, and its managing agency is usually charged with the responsibility of storing and managing the design drawings of the system. The drawings are important and historically valuable documents that must be kept permanently because they contain comprehensive data that is used to manage and maintain the system. However, no study has been performed in Korea on how well agencies are preserving and managing these records. Seoul Metropolitan Rapid Transit Corporation(SMRT) is the managing agency established by the city of Seoul to operate subway lines 5, 6, 7, and 8 more efficiently to serve its citizens. By the Act on Records Management in Public Institutions(ARMPI), SMRT should establish a records center to manage its records. Furthermore, all drawings produced by SMRT and other third party entities should be in compliance with the Act. However, SMRT, as a form of local public corporation, can establish a records center by its own way. Accordingly, the National Archives & Records Service(NARS) has very little control over SMRT. Therefore, the purpose of this study is to research and analyze the present state of storage and management of the drawings of metropolitan rapid transit in SMRT and is to find a desirable method of preservation and management for drawings of metropolitan rapid transit. In the process of the study, it was found that a records center is being considered to manage only general official documents and not to manage the drawings as required by ARMPI. SMRT does not have a records center, and the environment of management on the drawings is very poor. Although there is a plan to develop a new management system for the drawings, it will be non-compliant of ARMPI. What's happening at SMRT does not reflect the state of all other cities' metropolitan rapid transit records management systems, but the state of creation of records center of local public corporation is the almost same state as SMRT. There should be continuous education and many studies conducted in order to manage the drawings of metropolitan rapid transit efficiently by records management system. This study proposes a records center based on both professional records centers and union records centers. Although metropolitan rapid transit is constructed and managed by each local public corporation, the overall characteristics and processes of metropolitan rapid transit projects are similar in nature. In consideration of huge quantity, complexity and specialty of drawings produced and used during construction and operation of metropolitan rapid transit, and overlap of each local public corporation's effort and cost of the storage and management of the drawings, they need to be managed in a professional and united way. As an example of professional records center, there is the National Personnel Records Center(NPRC) in St. Louis, Missouri. NPRC is one of the National Archives and Records Administration's largest operations and a central repository of personnel-related records on former and present federal employees and the military. It provides extensive information to government agencies, military veterans, former federal employees, family members, as well as researchers and historians. As an example of union records center, there is the Chinese Union Dangansil. It was established by several institutions and organizations, so united management of records can be performed and human efforts and facilities can be saved. We should establish a professional and united records center which manages drawings of metropolitan rapid transit and provides service to researchers and the public as well as members of the related institutions. This study can be an impetus to improve interest on management of not only drawings of metropolitan rapid transit but also drawings of various public facilities.

A Review of Salvage Archaeology in Korea and a Joint Research and Excavation Plan for North Korean Cultural Heritage (남북 문화유산 조사 현황과 공동조사를 위한 제언)

  • Choi, Jongtaik;Seong, Chuntaek
    • Korean Journal of Heritage: History & Science
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    • v.52 no.2
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    • pp.20-37
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    • 2019
  • Three Inter-Korea summits and a North Korea-USA summit that were previously unexpected provide a basis for an optimistic outlook for the future development of Korean archaeology. While Korean archaeology has witnessed a great advance since the mid-20th century, it also exhibits significant weaknesses in explaining cultural changes in prehistory and the early historical period in the Korean Peninsula due to the paucity of information on archaeological evidence of North Korea. Recent development of favorable conditions for research and excavations of North Korean cultural heritage could be a valuable opportunity for Korean archaeology to overcome the current adversity. Especially, given the expected large-scale SOC industrial project in North Korea, we need to prepare for the systematic research and excavation of archaeological materials. The present essay attempts to provide a suggestion for the joint archaeological expeditions to excavate and manage cultural resources in North Korea based on a critical review of previous salvage excavations in South Korea, such as those conducted before the construction of the Korean rapid transit railway system (KTX). We suggest that professional archaeologists should be included in the project and oversee the planning and design of road and railway constructions and other SOC projects in order to minimize the cost of trial and error processes that were well exemplified by the KTX salvage excavations. The Korean Archaeological Society and North Korean Archaeological Society may organize a common association that will supervise joint archaeological expeditions. Importantly, The Korean Archaeological Society and other related institutions should prepare to build an organization that conducts impending archaeological excavation in North Korea. While we likely face challenges and difficulties during the various stages of archaeological research and excavations in North Korea, only through thorough and systematic preparation can we avoid the destruction of valuable cultural heritage and find an opportunity for the further development of Korean archaeology.

A Study on the Strategy for Enhancing the Service Export linked with Manufacturing Sector : focused on Stage System and Special Lighting Service (제조-서비스 연계형 수출상품화 모델 개발전략 - 무대장치 및 특수조명서비스 수출산업을 중심으로 -)

  • Park, Moon-Suh
    • International Commerce and Information Review
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    • v.10 no.4
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    • pp.457-491
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    • 2008
  • As stage equipment export markets along with special lighting service lack the attraction for already globally established businesses, such markets can be viewed as an advantageous opportunity for SMEs as in general. In reality, global businesses tend to focus on large construction projects and this indicates relatively less substantial markets such as stage equipment and special lighting service export are more suitable for SME businesses. However, possible problems may be recognized as following; doubtful capabilities by such businesses to join in the vast and competitive global market and pursue manufacturing and service based export. This point is also supported by the fact that such in general SME businesses have substantially less experience in exporting products and services abroad. Realizing the distinctive features of the Korean economy, it is unarguable that every sector and area of global market must be regarded and monitored closely. Hence, it can be argued that there is an imminent need for establishment of supportive institution to assist export process of combination of stage equipments and special lighting service. This study emphasizes the need to improve export process of stage equipments, special lighting services as well as other related products and services which have been focused in domestic market only until now. Further, it also analyzed the potential prospect of such direction reconciling current crisis our manufacturing industry is facing. Even though it maybe regarded as one of the niche market for export of Korea in the short term view, stage equipment and special lighting service industry may rapidly grow as the global cultural industries have grown along with the increase of national income earnings overall. Due to such advantageous features, it can be expected that such industries will show strong growth in the near future. After analyzing the fact that Korea's plants (eg. powerplants) export sector is at its boom, there is a need to transform stage equipment and special lighting service export market into a primary market from a secondary(niche) market for SMEs. This study is viewed from the Korean economic and export sector aspect in the aim of seeking a solution to conquest our realistic limit in our export sector by developing a suitable export model. There have been cases of very few attempts to expand abroad by SMEs who have failed miserably due to their failure to adapt to foreign culture, practice and languages as well as substantial lack in experience in export marketing. Despite this, neglecting our manufacturing industry as it is which is showing its limit and problems is out of option therefore, it is imminent that we come up with an effective measure to address this problem and service export can be suggested as one of them. This study reveals manufacturing-service export model of stage equipment and special lighting service and its related areas is recognized as a field with a very strong future and furthermore, it is expected to bring synergy effects in manufacturing and services sector as well. Further, the operation strategy contains combination, composition and fusion(convergence) of manufacturing and service sectors which could derive various of export products which displays greater success probability or this export model. The outcome of this research is expected to become a useful source for enterprises related to such industry which are seeking a possible global expansion. Furthermore, it is also expected to become a catalyst which fastens the process of global expansion and not only that, we are firmly assured that this study will become an opportunity to improve our current policies and institutions related to this area's export market.

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