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Collision Avoidance and Deadlock Resolution for AGVs in an Automated Container Terminal (자동화 컨테이너 터미널에서의 AGV 충돌 방지 및 교착 해결 방안)

  • Kang, Jae-Ho;Choi, Lee;Kang, Byoung-Ho;Ryu, Kwang-Ryel;Kim, Kap-Hwan
    • Journal of Intelligence and Information Systems
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    • v.11 no.3
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    • pp.25-43
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    • 2005
  • In modern automated container terminals, automated guided vehicle (AGV) systems are considered a viable option for the horizontal tansportation of containers between the stacking yard and the quayside cranes. AGVs in a container terminal move rather freely and do not follow fixed guide paths. For an efficient operation of such AGVs, however, a sophisticated traffic management system is required. Although the flexible routing scheme allows us to find the shortest possible routes for each of the AGVs, it may incur many coincidental encounters and path intersections of the AGVs, leading to collisions or deadlocks. However, the computational cost of perfect prediction and avoidance of deadlocks is prohibitively expensive for a real time application. In this paper, we propose a traffic control method that predicts and avoids some simple, but at the same time the most frequently occurring, cases of deadlocks between two AGVs. More complicated deadlock situations are not predicted ahead of time but detected and resolved after they occur. Our method is computationally cheap and readily applicable to real time applications. The efficiency and effectiveness of our proposed methods have been validated by simulation.

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A Study on Emergency Evacuation Route Planning and USN-Based Induction Activities of Correctional Facilities (교정시설의 비상시 피난경로계획 및 USN기반 대피유도활동에 관한 연구)

  • Park, Joo-Hyung;Park, Jong-Hyun
    • Fire Science and Engineering
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    • v.25 no.2
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    • pp.39-46
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    • 2011
  • In correctional facilities with majority of occupants in custody, the safe evacuation guide without getaway accidents should be very important due to complexity in escape paths. Fire causes are various in correctional facilities, for example, arson fire is a major cause in mental treatment facilities, however, old facilities or carelessness of flammable materials consist of fire causes in jail facilities. Both types of correctional facilities are the same in terms of many casualties from the fire cases. The thesis focus on escape paths and evacuation guide plans on the basis of analysis on fire cases and structural vulnerability, and then an electronic unlocking system is concededly installed for safe evacuation of occupants in custody without getaway accidents. Especially, the effect of the electronic unlocking system is going to be analyzed on the basis of RSET (required safe egress time) in order to realize for the occupants to evacuate safely to the front yard in case of emergency. In conclusion, if electronic security allowed system with USN (Ubiquitous Sensor Networks) technology should be installed in multi-storey correctional buildings, it is proposed that the occupants in custody might be a guided safely without getaway trials.

Factors Affecting the Resolution of Environmental Disputes and Relevant Policy Alternatives (환경분쟁해결에 영향을 미치는 요인과 정책대안)

  • Lee, Soo-Jang
    • Journal of Environmental Policy
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    • v.9 no.4
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    • pp.125-154
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    • 2010
  • Among the various contemporary issues that confront the nation or society, surely one of the most difficult to resolve are environmental disputes between government authorities, developers, local residents and advocacy groups. While such disputes can in some cases be the result of a selfish and illegal NIMBY("Not In My Back Yard") syndrome, they can also be an expression of rational and appropriate demands from local residents to preserve the ecology and quality of life for their communities, particularly with respect to the planning of "locally unwanted land uses(LULUs). Accordingly, rethinking NIMBYism entails several implications for planning of LULUs. Until the 20th century many planners considered only "functional rationality" in their decision making, in a confrontational "us versus them"process of "decide-announce-defend(DAD)". I believe, however, that a fair, voluntary, and negotiated process of alternative dispute resolution(ADR) based on consensus building is the means to resolving these disputes. A voluntary process is more desirable and feasible than a coercive one, making ADR well worth pursuing. From this perspective, I explore several factors which affect the resolution of environmental disputes. I suggest three main factors as follows: i) extension of citizen participation, ii) enhancement of equity, and iii) building of trust. Alternatives are presented based on these factors.

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Heavy Metal Contents in Soils and Vegetables in the Plastic Film House (시설재배지(施設栽培地) 토양(土壤) 및 채소류중(菜蔬類中) 중금속함량(重金屬含量) 조사(調査))

  • Jung, Goo-Bok;Jung, Ki-Yeol;Cho, Guk-Hyun;Jung, Beung-Gan;Kim, Kyu-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.30 no.2
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    • pp.152-160
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    • 1997
  • In order to monitor the content of heavy metals of soil and vegetable in the plastic film house, five hundred and twenty two soil, and 147 vegetable samples grown under plastic film house were collected for the analysis of heavy metals. The average contents of Cd, Cu, Pb, Zn and As in surface soil were 0.208, 3.69, 2.49, 23.3 and 0.65mg/kg, respectively. Cu and Zn contents of the soil were higher than those values measured for upland soils in 1989, however, these contents were lower than "Countermeasure values" (Cd:4, Cu:125, Pb:300, and As:15mg/kg in soil) for soil contamination indicators described in Soil Environmental Conservation Act of Korea(1996). The contents of Cd, Cu and Zn increased with increasing years of cultivation. The contents of Cd, Cu, and Zn in soils received pig manure compost were higher than those received the poultry or barn yard manure compost. The average contents of Cd, Cu, Pb, Zn and As in fresh vegetable plants ranged from 0.015 to 0.047, 0.341 to 0.802, 0.080 to 0.356, 1.08 to 8.04 and 0.021 to 0.059mg/kg, respectively.

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A Study on Analysis of the Preference of Container Ports in Northeast Asia - with the case of Busan Container Port - (동북아 경쟁항만들의 선호도 분석에 관한 연구 - 부산항을 중심으로 -)

  • Chung, Tae-Woo;Kwak, Kyo-Seok
    • Journal of Navigation and Port Research
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    • v.26 no.4
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    • pp.363-372
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    • 2002
  • Recently, mutual economy cooperation in Northeast Asia has leaded steady growth among main countries of it and rather promoted a single economy circle. In this region, Busan container port competes with min container ports in China, Taiwan and Japan in it for attracting transshipment container traffic of north-Shanghai in China and for-east Russia. Therefore, this paper aims to suggest competitive strategies for Busan container port to attract container traffic in Northeast Asia To do so, it evaluates the preference of important ports in the competitive situation and competitiveness edgy of important ports in Northeast Asia, and finally proposes the relative order of important factors. Based on the evaluation of it, first, the Busan ports hue tn strengthen port facilities to attract more traffic and in detail, reinforce the number of berth, yard areas and handling equipment Second, they also have to provide high quality of services to deliver cargos in time, not being damaged and swiftly response to shipowner and shipper's claim, Third, they need to review the strategy to adopt flexible tariff policy and to invest the profit from tariff in port service and facilities, as providing higher port tariff level by a regular rate.

Comparisons of Rates of Air Drying and Shed Drying for Chestnut and Paulownia Soundboards (밤나무와 오동나무 향판용재(響板用材)의 옥외(屋外) 옥내(屋內) 천연건조(天然乾燥) 속도(速度)의 비교(比較))

  • Jung, Hee-Suk;Yoo, Tae-Kyung
    • Journal of Korean Society of Forest Science
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    • v.87 no.4
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    • pp.577-583
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    • 1998
  • Chestnut and paulownia boards for the traditional musical instruments were air dried to compare moisture contents(MC), drying rates and drying times between the air drying for 70 days in a yard and the shed drying for 150 days in a closed shed when piled in early June. An average final MC and the drying rate of chestnut boards were 20.6 percent and 0.78%/day for the air drying, and 16.6 percent and 0.44%/day for the shed drying. An average final MC and the drying rate of paulownia boards were 16.7 percent and 1.53%/day for the air drying, and 13.5 percent and 0.77%/day for the shed drying. Drying rates of air-dried boards were nearly twice as high as those of shed-dried boards for both species. Air drying rates of chestnut and paulownia boards were very high and exhibited falling drying rate above the fiber saturation point(30%), and then decreased irregularly. However, shed drying rates of chestnut and paulownia boards were high and exhibited falling drying rate above 55 percent MC for chestnut boards and above 80 percent MC for paulownia boards, and then decreased irregularly.

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Cranes(Grus japonensis) Adopted as a Traditional Factor in Landscaping and Gardening Culture (전통조경요소로써 도입된 학(鶴)과 원림문화)

  • Kim, Hai-Gyoung;So, Hyun-Su
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.3
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    • pp.57-67
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    • 2012
  • This study draws the following conclusions about the nature garden culture with crane that is a dynamic landscaping factor introduced into nature garden by analyzing the literatures on cranes written and landscapes painted in Chosun Dynasty. First, crane symbolizes such Buddhist, Taoist and Confucius media as appearance of Buddha, desire for Taoist hermit world and long life, and a solitary's life of proud loneliness. It has been recorded that crane was raised from the Three Nations Era till the Japanese occupation and Confucius scholars in Chosun Dynasty opened shows concerning crane or formed literature groups enjoying poems of it, and often using crane as their denial of going into government service. Second, in order to introduce crane to nature garden, people caught wild crane and made a fence and some kind of pond for their growth. In addition, crane was strictly managed by appointed slaves and they trained crane for dancing and then tended to allow a crane to play on the yard in terms of abstract meaning or got two cranes free in consideration of their ecology. Third, for more appreciation of crane and the expression of some symbolism matching for it, both plum and pine, which mean a solitary's life and long life respectively, were planted in nature garden. And, Confucius scholars in Chosun Dynasty also enjoyed their refined tastes with appreciation, napping, reading and playing the harp, accompanied by crane. As aforementioned, Confucius scholars in Chosun Dynasty did not only draw the meaning symbolized by cranes and write poems about such symbolic meaning, but also positively introduce crane into nature garden as a dynamic landscaping factor, so that they enjoyed synesthetic senses including looks, motions and sounds of cranes for their refined tastes.

Manufacturing Multi-degradable Food Packaging Films and Their Degradibility (복합분해성 플라스틱 식품포장 필름의 제조 및 분해성)

  • Chung, Myong-Soo;Lee, Wang-Hyun;You, Young-Sun;Kim, Hye-Young;Park, Ki-Moon
    • Korean Journal of Food Science and Technology
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    • v.35 no.5
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    • pp.877-883
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    • 2003
  • Multi-degradable master hatch (M/B) was prepared and 0.05 mm polyethylene (PP) food packaging films containing 0, 10, and 20% M/B were manufactured by inflation film processing. The films were exposed to UV radiation, fungi, and heat in order to observe their photolysis, biodegradability, and thermal degradability, respectively. While pure PP film maintained more than 70% of its original elongation after 8 weeks of UV radiation, an almost perfect loss in the elongation of PP film containing 20% M/B was observed. Significant decreases in elongation of PP films by heat treatment $(68{\pm}2^{\circ}C)$ were also found in samples containing the multi-degradable M/B. By observing changes in film surface after the inoculation of fungi using scanning electron microscopy (SEM), the biodegradability of plastic film could be accelerated with the addition of multi-degradable M/B. The results of the mulching test in yard showed that adding multi-degradable M/B can effectively degrade plastic films in natural environmental conditions without interrupting the growth of plants.

Importance and Performance Analysis on Factors of PC Component Allocation and Loading Planning (IPA를 통한 PC부재 할당 및 적재 계획 시 고려사항 분석)

  • Jang, JunYoung;Cho, Kyeong Woon;Koo, Choongwan;Lee, Chansik;Kim, Taewan
    • Korean Journal of Construction Engineering and Management
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    • v.22 no.2
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    • pp.53-62
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    • 2021
  • PC component allocation and loading plan can contribute to reductions in carbon dioxide emission and energy use of vehicles and total project costs with increased utilization of vehicle loading space. The study derived 18 considerations that PC construction plant managers and site managers take into account when they plan allocation and loading of PC components. Then, IPA (Importance and Performance Analysis) was performed to assess importance and performance of the 18 considerations. Results show that in the PC component allocation planning, considerations regarding the number of vehicles and existence of yard for storing PC components have not been taken into account well by the managers. In the PC component loading planning, PC component loading direction has not been reflected well by the managers although it is considered important by them. Recently, ill-planning issues of PC component transportation, such as inefficient use of vehicle space and loading with low stability, are frequent due to various types of PC components produced. In this context, if the results of this study are reflected in the development of component allocation and loading planning, vehicle management of PC projects would be more efficient, thereby leading to economic project management.

Basic study of new concept environment-friendly pile foundations with earthquake resistant foundation and lateral reinforcement on rapid-transit railway bridge (고속철도교 기초 내진 및 수평저항성능 보강형 신개념 친환경말뚝 신공법의 실용화 기초연구)

  • SaGong, Myung;Paik, Kyu-Ho;Lim, Hae-Sik;Cho, Kook-Hwan;Na, Kyung
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.880-894
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    • 2010
  • The Grout injected precast pile is widely used in rapid-transit railway bridge recently. The existing portland cement of well used filling at injected precast method that with low strength and environmental pollution, unstable in which ground water contamination by cement flow out, ground relaxation by water down, decrease of horizontality resistance and durability and load transfer divide etc. In particular, as in rapid-transit railway bridge need to secure safety from different angle with vibration of high speed train, horizontal force when train stop and earthquake. Works of foundation construction consider to requirements of the times to coal yard green growth. Together, new green foundation method for possible economics and securing of reduce the term of works are material to developments. Therefore, we carried out study that it is using and development new concept environment - friendly filling include durability and earthquake resistance, for secure safety and minimize environment pollution. To achieve this, we carried out difference tests that new green fillings of underwater concrete, high liquidity, high viscosity, early stiffness as compared to existing portland cement fillings. As results, new green filling have outstanding application at precast pile method and micropile construction method with vertical bearing capacity, horizontal bearing capacity and many case. From now on we will be looking forward to development of new environment-friendly foundation method from various further studies.

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