• Title/Summary/Keyword: Construction Infra

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Design and Performance Evaluation of Open Information Retrieval Service System (개방형 정보검색시스템의 설계 및 성능분석)

  • Kim, Dong-Won;Ryu, Won;Jeon, Kyung-Pyo;Bae, Hyeon-Deok
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.7
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    • pp.1812-1821
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    • 1996
  • In this paper, firstly we describe the structure and the performance of our ICPS(Information Communicaion Processing System) which currently provides information retrieval services, and then make a proposal for the construction of the open-networking information communication infra-structure which enables us to fully pre-pare for the emerging information society. In detail, the structure and the methodology needed for the implementation of the billing function on behalf of all information providers by using the user access network number as a user identification number while guaranteeing the equivalent access to the multiple value-added networks, are suggested. Based on the above ideas, the AICPS(Advanced Information Communication Processing System) has been designed and implemented. Final system performance evaluation with the assumption of a poling system as a system model, shows that our system can handle 10,000 user simultaneously who are using V.34 28.8 kbps modems and the processing capacity is 288,000 packet/sec. This result is so far superior to our target performance established during the desingning procedure. Namely, our system was originally designed to accommodate only 960 users at the same time. By taking advantage of this excessive high performance of our system, many other users can easily access the new services which are accessible only throught the ISDN or the Internet.

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Object-oriented Road Field BIM Standard Object Classification System Suggest Development Plan (객체지향의 도로분야 BIM 표준객체분류체계 개발방안)

  • Nam, Jeong-Yong;Kim, Min-Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.119-129
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    • 2018
  • The Ministry of Land, Transport and Maritime Affairs has promulgated the mandatory design of BIM for road projects of more than 50 billion won by 2020 under the Basic Plan for the Sixth Construction Technology Promotion. As a result, major public clients are attempting to implement BIMs that are appropriate to the situation of each institution. On the other hand, it is difficult to design and construct a proper BIM and accumulate BIM information of the ordering organization because the technical guidelines and standard classification system that can perform BIM effectively have not been presented sufficiently. The characteristics of the road should be managed systematically, e.g., atypical objects, such as earthworks, which are constantly changing along a line; large objects, such as bridges and tunnels; and facilities, such as signs and soundproof walls. To achieve this, a multitude of standard systems should be developed and disseminated, but there have been insufficient studies on practical methods. To solve this problem, this study developed a BIM standard object classification system in the road sector to meet the international standard, accommodate a multi-dimensional information system, and provide a more effective BIM standard information environment that can be utilized easily by practitioners.

Capsule Train Dynamic Model Development and Driving Characteristic Analysis Considering the Superconductor Electrodynamic Suspension (초전도 유도 반발식 부상특성을 고려한 캡슐트레인 동특성 해석 모델 구축 및 주행 특성 분석)

  • Lee, Jin-Ho;Lim, Jungyoul;You, Won-Hee;Lee, Kwansup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.38-45
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    • 2020
  • A magnetically levitating capsule train, which runs inside the sub-vacuum tube, can reach ultra-fast speeds by dramatically reducing the aerodynamic drag and friction. The capsule train uses the superconductor electrodynamic suspension (SC-EDS) method for levitation. The SC-EDS method has advantages, such as a large levitation gap and free of gap control, which could reduce the infra-construction cost. On the other hand, disadvantages, such as the large variation of the levitation-guidance gap and small damping characteristics in levitation-guidance force, could degrade the running stability and ride comfort of the capsule train. In this study, a dynamic analytical model of a capsule train based on the SC-EDS was developed to analyze the running dynamic characteristics. First, as important factors in the capsule train dynamics, the levitation and guidance stiffness in the SC-EDS system were derived, which depend non-linearly on the velocity and gap variation. A 3D dynamic analysis model for capsule trains was developed based on the derived stiffness. Through the developed model, the effects of the different running speeds on the ride comfort were analyzed. The effects of a disturbance from infrastructure, such as the curve radius, tube sag, and connection joint difference, on the running stability of the capsule train, were also analyzed.

Estimation of the amount of refrigerant in artificial ground freezing for subsea tunnel (해저터널 인공 동결공법에서의 냉매 사용량 산정)

  • Son, Youngjin;Choi, Hangseok;Ko, Tae Young
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.2
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    • pp.255-268
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    • 2018
  • Subsea tunnel can be highly vulnerable to seawater intrusion due to unexpected high-water pressure during construction. An artificial ground freezing (AGF) will be a promising alternative to conventional reinforcement or water-tightening technology under high-water pressure conditions. In this study, the freezing energy and required time was calculated by the theoretical model of the heat flow to estimate the total amount of refrigerant required for the artificial ground freezing. A lab-scale freezing chamber was devised to investigate changes in the thermal and mechanical properties of sandy soil corresponding to the variation of the salinity and water pressure. The freezing time was measured with different conditions during the chamber freezing tests. Its validity was evaluated by comparing the results between the freezing chamber experiment and the numerical analysis. In particular, the freezing time showed no significant difference between the theoretical model and the numerical analysis. The amount of refrigerant for artificial ground freezing was estimated from the numerical analysis and the freezing efficiency obtained from the chamber test. In addition, the energy ratio for maintaining frozen status was calculated by the proposed formula. It is believed that the energy ratio for freezing will depend on the depth of rock cover in the subsea tunnels and the water temperature on the sea floor.

Development of DHLT Joint for Vertical Cutoff Walls in Offshore Waste Landfill Site (해상처분장 연직차수공을 위한 DHLT 이음부의 개발)

  • Hong, Young-Ho;Lee, Jong-Sub;Lee, Dongsoo;Chae, Kwang-Seok;Yu, Jung-Doung
    • Journal of the Korean Geotechnical Society
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    • v.34 no.3
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    • pp.43-56
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    • 2018
  • Vertical cutoff walls such as steel pipe sheet piles (SPSPs) have been commonly applied for the construction of the offshore waste landfill site. Because the SPSPs are sequentially installed by connecting their joints to those of adjacent piles, their mechanical stability should be ensured against the inherent external forces on the sea. The objective of this study is to evaluate the structural performances of the newly developed types of SPSP joint compared with those of other joint types. The problems of the traditional SPSP joints are investigated, and an advanced joint shape of SPSP, which is named double H with L-T (DHLT) joint, are designed for improving the constructability and maintenance. Full-scale models of the DHLT joint are manufactured, and then its joint areas are filled with grout material. After 28 days of curing time, compressive and tensile strength tests were performed on the joint models and the test results were compared with those of the traditional joints. Experimental results show that the structural capacities of the DHLT joint models are lower than those of traditional joints due to the influence of grout and steel members. In the cases of the compressive strength test, especially, bending occurs on steel H-beam with no distinct cracks in grout due to the asymmetrical structure of joint which has no reaction force. This study shows that the performance of the SPSP joint can be improved by considering the influence factors on the structural capacities estimated by the experimental tests.

The Impact of Culture Resources on City Brand Personality, Relationship Quality, and Loyalty in Tourism City (관광도시 문화자원의 도시브랜드개성, 관계품질, 충성도에 미치는 영향)

  • Kim, Jung-Hee;Kim, Hyoung-Gil
    • Science of Emotion and Sensibility
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    • v.13 no.4
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    • pp.741-752
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    • 2010
  • City culture resources are critical elements to city brand strategies for improving city attraction and provide much contribution to induce visitors from competitive city. A city brand needs to be distinguished and differentiated from competing cities because they are all engaged in the similar environment of city. The differentiation of brand achievement has become increasingly important to highlight certain brand functions to include emotional, self-expressive, and symbolic functions since the importance of such functions has been further emphasized in promoting tourism activities. In particular, That is the recent role of city brand personality that has been emphasized in city management. In other words, visitors now freely and actively express their personalities or egos in tourism activities, taking an important role in construction of a brand asset. The study examines how culture resources affect city brand personality, relationship quality, and city brand royalty in the tourism city. The authors test the proposed model using data from Jeju tourists. The pivotal findings via the structural equation model in the study are as follows; 1) culture resources have been classified culture programs, culture infra, human resources, 2) The city brand personality has been classified as innovativeness, peacefulness, sophistication, confidence and dynamics; 3) The culture resources influenced on the city brand personality; 4) The city brand personality influenced on the satisfaction and involvement; 5) The satisfaction and involvement influenced on the loyalty. Results from the empirical study indicates that culture resources have a strong positive impaction on city brand personality. To increase tourist' royalty of city brand personality, managements must manage culture effectively and create friendly city brand personality to in accord with tourist needs.

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Effect of N Value and Pile Length Ratio on Bearing Capacity Distribution of Cohesionless Soil (사질토 지반에서 N값과 말뚝의 길이비가 지지력 분담 특성에 미치는 영향)

  • Lee, Kwang-Wu;You, Seung-Kyong;Han, Jung-Geun;Park, Jeong-Jun;Kim, Ki-Sung;Hong, Gigwon
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.1
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    • pp.65-73
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    • 2020
  • This study describes the evaluation results of pile length ratio and N value on the bearing capacity of drilled shafts in cohesionless soil. The bearing capacity ratio in Meyerhof's formula is affected only by the length ratio, and it is equally evaluated a sharing ratio of the end bearing capacity and the skin friction. NAVFAC's formula shows that the pile length influences both end bearing capacity and the skin friction, but pile length is also found to be a more influence factor on the end bearing capacity. Especially, it was found that the effect of pile length factor was larger than the effect of N value and pile diameter. FHWA's formula was evaluated to reflect the influence factor by skin friction more positively than other formulas at calculation the bearing capacity. It was also confirmed that the influence of the skin friction is larger when the ultimate bearing capacity is evaluated.

Behavior of braced wall due to distance between tunnel and wall in excavation of braced wall nearby tunnel (터널에 인접한 흙막이굴착 시 터널 이격거리에 따른 거동특성)

  • Ahn, Sung Joo;Lee, Sang Duk
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.4
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    • pp.657-669
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    • 2018
  • In recent years, the development of complex urban areas has become saturated and much attention has been focused on the development of underground space, and deep excavation is frequently performed in order to increase the utilization of underground space due to the enlargement of buildings and the high rise of buildings. Therefore, in this study, we tried to understand the behavior of the braced wall and the behavior of the tunnel adjacent to the wall according to the stiffness of the wall and the distance between the tunnel and wall. As a result of the study, the deformation of the braced wall tended to decrease with increasing the stiffness of the wall, and the axial force acting on the struts was also different according to the stiffness of braced wall. When the stiffness of the braced wall is small (2 mm), the point at which the axial force of the braces maximizes is near 0.3H of the wall. When the stiffness of the braced wall is large (5 mm), the axial force is maximum at around 0.7H of the wall. Also, the tunnel convergence occurred more clearly when the separation distance from the braced wall was closer, the stiffness of the wall was smaller, and the tunnel convergence was concentrated to the lower right part. The ground settlement due to the excavation of the ground tended to decrease as the distance between tunnel and braced wall was closer to that of the tunnel, which is considered to be influenced by the stiffness of the tunnel.

Basic Study on Bridge Asset Management Framework and LOS for Efficient Downtown Bridge Maintenance (효율적인 도심지 교량관리를 위한 교량자산관리 체계 및 서비스수준(LOS) 개발을 위한 기초연구)

  • Kim, Gyung-Hyun;Kim, Dong-Jin;Lim, Jong-Kwon;Park, Mi-Yun;Lee, Min-Jae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.5
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    • pp.671-679
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    • 2016
  • Bridges, which constitute one of the key facilities in a social infrastructure, are easily accessed and used by users, so that keeping their performance above a certain level is essential. According to various cases in the U.S., Japan and Europe with a long construction history, it is expected that the maintenance cost of bridges in Korea will increase continuously in the future, so a rational decision making system based on engineering factors is necessary to optimize the performance of and maintain them by allocating the limited budget efficiently. This study is a preliminary basic study for the purpose of developing a common asset management system for managing all of the bridges and maintaining the level of service provided by them. The scope of this preliminary study is limited to bridges in urban areas. The bridge asset management system for bridges in urban areas, their level of service (LOS) and performance measure (PM) were developed by carrying out a workshop consisting of both experts and stakeholders. The analysis on the weights of the value and performance measure for each performance indicator was carried out by using the multi-attribute utility theory and the AHP method. In order to confirm the application of the weight of the performance measure and value of the performance indicator, six bridges in an example city were selected, LOS analysis was applied and its results were reviewed.

A Study on the Guidelines for the Development of Domestic Flight Test Operation Manual (국내 비행시험 운영 매뉴얼 개발 기준 연구)

  • Kim, Mu-Geun;Baek, Seung-Don;Song, Chan-Yong;Ahn, Dae-Whee;Han, Jeongho;Yoo, Beong-Seon;Kang, Ja-Young
    • Journal of Advanced Navigation Technology
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    • v.23 no.4
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    • pp.281-288
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    • 2019
  • A Flight test is an important process that must be performed to maintain airworthiness in the aircraft lifecycle, including aircraft development and certification. Flight test can be conducted for the purpose of demonstrating or verifying compliance with the applicable standard. Results of the flight test air accident analysis confirm that it is caused by a combination of various factors as well as aircraft. The International Civil Aviation Organization recommends the establishment and implementation of a safety management system to prevent aircraft accidents, but it does not reflect the specificity of the flight test. As such, advanced countries are providing separate criteria to assist stakeholder in conducting flight test safety management. This study investigates and analyzes relevant regulations of advanced countries, in accordance with the construction of a national flight performance test site in Korea, and proposes government-level guidelines to help stakeholders develop their flight test operation manuals. The guidelines discuss topics such as organizational composition, safety and risk management, flight operation, personnel management, and administrative issues.