• Title/Summary/Keyword: Construction delay

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Study on Korean Variable Message Format Construction for Battlefield Visualization (전장가시화를 위한 한국형 지상전술데이터링크 구축 연구)

  • Kim, Seung-Chun;Lee, Hyung-Keun
    • Journal of IKEEE
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    • v.15 no.1
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    • pp.104-112
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    • 2011
  • During the ground operation of Korean army, the voice message is mainly used for exchanging informations related to the surveillance and reconnaissance, command and control, and precision strike. However, in order to the battlefield visualization among fighting powers participating in the ground force operation, automatic situational awareness and variable message format (VMF) for command and control are required. For securing core technologies necessary for the battlefield visualization, message standard and message handler are established through several applied researches. Besides, the VMF for equipping a weapon system is in development. In this paper, a study on the Korean variable message format (KVMF), where interoperability of integrated battle management system (BMS) is guaranteed due to performing joint, ground, and combined operations so that the situation awareness and strike system can be automated in almost real time, is presented. From the modeling and simulation (M&S) results of the message processor, delay time is varied in accordance with the number of nodes in unit platoon network, message length, and generation interval of routine messages. Therefore, it is shown that the system performance can be optimized by establishing proper network protocol for each situation.

Hydration and Compressive Strength of High-volume Fly Ash Cement Paste (하이볼륨 플라이애시 시멘트 페이스트의 수화 및 압축강도 특성)

  • Hwang, Chul-Sung;Moon, Eun-Jin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.5
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    • pp.156-162
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    • 2017
  • Recently, researches on High-Volume Fly ash Cement(HVFC), which is replacing high portion of cement to fly ash, have been actively conducted to reduce $CO_2$ formation. Though HVFC has various advantages, low strength development in early ages is pointed out as the biggest problem in the application of fly ash. In order to overcome such limitations, this study investigated the hydration and compressive strength characteristics of HVFC paste depending on the fly ash content with the mixing ratio varying from 0 to 80 %. Experimental results show that the HVFC paste with low water-binder ratio can overcome the limitation of low compressive strength at early ages. Also, from the result of heat flow delay, 50 % of fly ash weight ratio was the critical point of the filler effect.

Characterization of Repairing PVC profile for Trenchless Sewer Pipeline (비굴착 하수관로용 PVC 프로파일 보수재 특성 평가)

  • Park, Joon-Ha;Jeon, Sang-Ryeol;Lee, Kwan-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.7
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    • pp.4977-4983
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    • 2015
  • The full depth excavation induces couple of technical and social problems like increase of construction cost and time for excavation and backfill, increase of public complains and delay of traffic, and so force. In order to overcome these problems, lots of laboratory tests were carried out for sewer pipeline of maintenance materials with trenchless methods. The testing materials are PVC strip and then the lab tests were followed by Korean Standard. We will treat the structure safety and pipe integrity of PVC profile more excellent than the profile have application to SPR. There is no side-effect to process and to satisfy the criteria of tensile strength, impact strength and softening temperature. The profile with resin adhesive showed no leakage of water at specific pressure.

A Study of the Court-Annexed ADR and Its Implications in the United States (미국의 사법형 ADR제도와 그 함의에 대한 연구)

  • Kim, Chin-Hyon;Chung, Yong-Kyun
    • Journal of Arbitration Studies
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    • v.21 no.3
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    • pp.55-87
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    • 2011
  • This paper is to illustrate a variety of court-annexed ADR programs and vindicate its implications of court-annexed ADR in United States. It has been almost three decades since Frank Sender articulated his vision of the multi-door courthouse. The court-annexed ADR originated from the concept of multi-door court house. Professor Sander argued that the court must transform from the court that provides litigation, only one type of dispute resolution, to the multi-door courthouse which provides a variety of dispute resolution methods including a number of ADR programs. The types of court-annexed ADR on which this paper focus are court-annexed mediation, court-annexed arbitration, mini trial, early neutral evaluation(ENE), summary jury trial, rent-a-judge, and med-arb in United States. The findings of this paper is as follows. First, the ADR movement is the irreversible and dominant phenomenon in the US court. The motivation of incorporating ADR into court is to reduce the cost of court to handle the civil disputes and to eliminate the delay of litigation process in the court. At the same time, a couple of studies of ADR revealed that the ADR program satisfied users of ADR. Second, the landscape of ADR has not been fixed. In 1970's, the court-annexed arbitration has been popular. In 1980's, the diverse kinds of ADR programs were introduced into the federal court as well as state courts, such as mini trial, early neutral evaluation(ENE), summary jury trial, and court-annexed mediation. But in 2000s, the court-annexed mediation has been the dominant type of ADR in United States. Third, the each type of ADR program has its own place for the dispute resolution. Since Korean society enters into the stage in which diverse kind of disputes occur in the areas of environment, construction, medicare, etc, it is desirable to take into consideration of the introduction of ADR to dispute resolution in Korea.

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Evaluation of Early age Performance of Geogrid-reinforced Asphalt Pavements (섬유그리드 보강 아스팔트 포장 초기 공용성 평가)

  • Yeo, Hyun-Dong;Kim, Gwang-Duk;Kwon, Soo-Ahn;Jeong, Jin-Hoon
    • International Journal of Highway Engineering
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    • v.12 no.4
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    • pp.53-60
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    • 2010
  • Geogrid-reinforced asphalt pavement is a pavement type applicable to overlay for repair in addition to new construction. The geosynthetic materials are placed between the asphalt layers to stop or delay propagation of the cracking existing at lower layers and to reduce the rutting. In this study, the cracking, rutting, IRI, and deflection were investigated to compare the performance between geogrid-reinforced asphalt pavement and ordinary or polymer modified asphalt pavement. Based on field conditions, the 11 sections were classified into 3 groups; sections proper to compare, sections with restrictions to compare, sections with difficulties in comparing, and the data was statistically analyzed. Larger resistance to rutting and increased IRI were measured at the geogrid-reinforced asphalt pavement sections comparing to the ordinary or polymer modified asphalt pavement sections. However, the deflections of the pavements were similar and the resistance to the cracking could not be compared because of short pavement lives.

An Analysis of Error Factors for Software Based Pseudolite Time Synchronization Performance Evaluation (소프트웨어 기반 의사위성 시각동기 기법 성능평가를 위한 오차 요소 분석)

  • Lee, Ju Hyun;Lee, Sun Yong;Hwang, Soyoung;Yu, Dong-Hui;Park, Chansik;Lee, Sang Jeong
    • Journal of Advanced Navigation Technology
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    • v.18 no.5
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    • pp.429-436
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    • 2014
  • This paper proposes three methods of the time synchronization for Pseudolite and GPS and analyzes pseudolite time synchronization error factors for software based performance evaluation on proposed time synchronization methods. Proposed three time synchronization methods are pseudolite time synchronization station construction method, method by using UTC(KRIS) clock source and GPS timing receiver based time synchronization method. Also, we analyze pseudolite time synchronization error factors such as errors of pseudolite clock and reference clock, time delay as clock transmission line, measurement error of time interval counter and error as clock synchronization algorithm to design simulation platform for performance evaluation of pseudolite time synchronization.

A Time Synchronization Method of Sensor Network using Single Flooding Algorithm (단일 플러딩 라우팅 알고리즘을 활용한 센서 네트워크의 시간 동기화 기법)

  • Shin, Jae-Hyuck;Kim, Young-Sin;Jeon, Joong-Nam
    • The KIPS Transactions:PartC
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    • v.18C no.1
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    • pp.15-22
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    • 2011
  • Usually time synchronization is performed after routing tree is constructed. This thesis proposes a time synchronization algorithm combined with single-flooding routing tree construction algorithm in a single path. TSRA (Time Synchronization Routing Algorithm) uses routing packets to construct a routing tree. Two types of time information are added to the routing packet: one is the packet receiving time, and the other is the packet sending time. Time offset and transmission time-delay between parent node and child node could be retrieved from the added time information using LTS (Lightweight Time Synchronization) algorithm. Then parent node sends the time offset and transmission time to children nodes and children nodes can synchronize their time to the parent node time along the routing tree. The performance of proposed algorithm is compared to the TPSN (Timing-sync Protocol for Sensor Networks) which is known to have high accuracy using NS2 simulation tool. The simulation result shows that the accuracy of time synchronization is comparable to TPSN, the synchronization time of all sensor nodes is faster than TPSN, and the energy consumption is less than TPSN.

Effects of High-harmonic Components on the Rayleigh Indices in Multi-mode Thermo-acoustic Combustion Instability

  • Song, Chang Geun;Yoon, Jisu;Yoon, Youngbin;Kim, Young Jin;Lee, Min Chul
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.4
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    • pp.518-525
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    • 2016
  • This paper presents the characteristics of non-fundamental multi-mode combustion instability and the effects of high-harmonic components on the Rayleigh criterion. Phenomenological observations of multi-harmonic-mode dynamic pressure waves regarding the intensity of harmonic components and the source of wave distortion have been explained by introducing examples of second- and third-order harmonics at various amplitudes. The amplitude and order of the harmonic components distorted the wave shapes, including the peak and the amplitude, of the dynamic pressure and heat release, and consequently the temporal Rayleigh index and its integrals. A cause-and-effect analysis was used to identify the root causes of the phase delay and the amplification of the Rayleigh index. From this analysis, the skewness of the dynamic pressure turned out to be a major source in determining whether multi-mode instability is driving or damping, as well as in optimizing the combustor design, such as the mixing length and the combustor length, to avoid unstable regions. The results can be used to minimize errors in predicting combustion instability in cases of high multi-mode combustion instability. In the future, the amount of research and the number of applications will increase because new fuels, such as fast-burning syngases, are prone to generating multi-mode instabilities.

A Case Study of Blasting with Electronic Detonator (전자뇌관을 활용한 발파 시공 사례)

  • Hwang, Nam-Sun;Lee, Dong-Hoon;Lee, Seung-Jae
    • Explosives and Blasting
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    • v.34 no.4
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    • pp.40-45
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    • 2016
  • Sites, where explosives are used, are constantly under constraint of vibration and noise levels. If a sensitive area is located nearby the sites, mechanical excavation has been preferred rather than blasting. Recently, however, blasting using electronic detonators is applicable in the areas, where previously should be excavated by mechanical methods. $HiTRONIC^{TM}$ is a fourth-generation detonator that utilizes Hanwha Corporation's advanced electronic technology. The detonator contains IC-Chip, which allows delay times between 0~15,000ms with 1ms interval. Furthermore, the product can provide high accuracy(0.01%) for accurate-blasting. Electronic detonator is widely used in highway and railway construction sites, large limestone quarries, and other works. In this paper, several sites, in which HiTRONIC was used, are introduced in order to enhance understanding of electronic detonator.

A case study on the arbitration awards canceled by Korean Supreme Court (중재판정이 대법원에 의해 취소된 사례연구)

  • Shin, Han-Dong
    • Journal of Arbitration Studies
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    • v.21 no.1
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    • pp.33-56
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    • 2011
  • Korea Supreme Court has cancelled four cases of thirty-nine Arbitral awards made by Korean Commercial Arbitration Board since Korea arbitration act was enacted in 1966. Three cases of them were cancelled by the reason of the arbitrator's disqualification in relation to impartiality or independence and the other to arbitration agreement enable to select the lawsuit or arbitration. When a person is approached in connection with his possible appointment as an arbitrator or has already been appointed as such, he shall without delay disclose all circumstances likely to give rise to justifiable doubts as to his impartiality or independence according to the one of the article 13 of Korean Arbitration Act. Upon being notified of the appointment as an arbitrator, each arbitrator shall immediately disclose in writing to the Secretariat any circumstances which might cause reasonable doubt about impartiality or independence. An arbitration agreement shall be made clearly and in writing not to appeal to the court or to be brought in the court. However most of the korean construction contracts have the arbitration agreement clause enable to appeal to the court or the arbitration on government official's advice. Many of these disputes are resolved by litigation after the precedent(Law case number : 2003da318) set by the Supreme Court on August 22, 2003 between the Korea(government) and the Korea Railroad or abandoned its attempt to arbitration. But each year, about four hundreds of arbitration business transactions were resolved arbitration, the voluntary submission of a dispute to an impartial person or persons for final and binding determination. Arbitration has proven to be an effective way to resolve these disputes privately, promptly, and economically.

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