• Title/Summary/Keyword: construction engineers

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A Study on Field Applicability of Underground Electric Heating Mesh (매설용 전기 발열 매시의 융설 효과에 대한 현장 적용성 연구)

  • Suh, Young-Chan;Seo, Byung-Seok;Song, Jung-Kon;Cho, Nam-Hyun
    • International Journal of Highway Engineering
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    • v.15 no.2
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    • pp.19-27
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    • 2013
  • PURPOSES : This study aims to investigate the snow-melt effects of an underground electric heater's snow-melt system via a field performance test, for evaluating the suitability of the system for use on a concrete pavement. The study also investigates the effectiveness of dynamic measures for clearing snow after snowfall events. METHODS : In order to check the field applicability, in November 2010, specimens were prepared from materials used for constructing concrete pavements, and underground electric heating meshes (HOT-mesh) were buried at depths of 50 mm and 100 mm at the site of the Incheon International Airport Construction Research Institute. Further, an automatic heating control system, including a motion sensor and pavement-temperature-controlled sensor, were installed at the site; the former sensor was intended for determining snow-melt effects of the heating control system for different snowfall intensities. Pavement snow-melt effects on snowy days from December 2010 to January 2011 were examined by managing the electric heating meshes and the heating control system. In addition, data on pavement temperature changes resulting from the use of the heating meshes and heating control system and on the dependence of the correlation between the outdoor air temperature and the time taken for the required temperature rise on the depth of the heating meshes were collected and analyzed. RESULTS : The effects of the heating control system's preheat temperature and the hot meshes buried at depths of 50 mm and 100 mm on the melting of snow for snowfalls of different intensities have been verified. From the study of the time taken for the specimen's surface temperature to increase from the preheat temperature ($0^{\circ}C$) to the reference temperature ($5{\sim}8^{\circ}C$) for different snowfall intensities, the correlation between the burial depth and outdoor air temperature has been determined to be as follows: Time=15.10+1.141Depth-6.465Temp CONCLUSIONS : The following measures are suggested. For the effective use of the electric heating mesh, it should be located under a slab it may be put to practical use by positioning it under a slab. From the management aspect, the heating control system should be adjusted according to weather conditions, that is, the snowfall intensity.

Bond Characteristics at the Interface between HMA Surface and RCC Base (아스팔트 표층과 RCC 기층 계면에서의 부착특성 연구)

  • Hong, Ki;Kim, Young Kyu;Bae, Abraham;Lee, Seung Woo
    • International Journal of Highway Engineering
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    • v.19 no.6
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    • pp.37-46
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    • 2017
  • PURPOSES : A composite pavement utilizes both an asphalt surface and a concrete base. Typically, a concrete base layer provides structural capacity, while an asphalt surface layer provides smoothness and riding quality. This pavement type can be used in conjunction with rollercompacted concrete (RCC) pavement as a base layer due to its fast construction, economic efficiency, and structural performance. However, the service life and functionality of composite pavement may be reduced due to interfacial bond failure. Therefore, adequate interfacial bonding between the asphalt surface and the concrete base is essential to achieving monolithic behavior. The purpose of this study is to investigate the bond characteristics at the interface between asphalt (HMA; hot-mixed asphalt) and the RCC base. METHODS : This study was performed to determine the optimal type and application rate of tack coat material for RCC-base composite pavement. In addition, the core size effect, temperature condition, and bonding failure shape were analyzed to investigate the bonding characteristics at the interface between the RCC base and HMA surface. To evaluate the bond strength, a pull-off test was performed using different diameters of specimens such as 50 mm and 100 mm. Tack coat materials such as RSC-4 and BD-Coat were applied in amounts of 0.3, 0.5, 0.7, 0.9, and $1.1l/m^2$ to determine the optimal application rate. In order to evaluate the bond strength characteristics with temperature changes, a pull-off test was carried out at -15, 0, 20, and $40^{\circ}C$. In addition, the bond failure shapes were analyzed using an image analysis program after the pull-off tests were completed. RESULTS : The test results indicated that the optimal application rate of RSC-4 and BD-Coat were $0.8l/m^2$, $0.9l/m^2$, respectively. The core size effect was determined to be negligible because the bond strengths were similar in specimens with diameters of 50 mm and 100 mm. The bond strengths of RSC-4 and BD-Coat were found to decrease significantly when the temperature increased. As a result of the bonding failure shape in low-temperature conditions such as -15, 0, and $20^{\circ}C$, it was found that most of the debonding occurred at the interface between the tack coat and RCC surface. On the other hand, the interface between the HMA and tack coat was weaker than that between the tack coat and RCC at a high temperature of $40^{\circ}C$. CONCLUSIONS : This study suggested an optimal application rate of tack coat materials to apply to RCC-base composite pavement. The bond strengths at high temperatures were significantly lower than the required bond (tensile) strength of 0.4 MPa. It was known that the temperature was a critical factor affecting the bond strength at the interface of the RCC-base composite pavement.

Construction of CORBA Object-Group Platform for Distributed Real-Time Service (분산 실시간 서비스를 위한 CORBA 객체그룹 플랫폼의 구축)

  • Kim, Myung-Hee;Joo, Su-Chong
    • Journal of KIISE:Computing Practices and Letters
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    • v.7 no.6
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    • pp.602-613
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    • 2001
  • Recently, the computing has developing in distributed object computing environment for supporting a programming paradigm of distributed application requiring interoperability between heterogeneous clients and servers. It involves the complex networking and the object-oriented technologies for various multimedia application service. In this paper, we construct the real-time object group platform for solving the difficulties of managements of distributed objects and the real-time constraints by requiring for real-time service supporting of applications in distributed computing environment. The existing researches are being tried to only improving the performance of systems by using real-time CORBA itself, or modifying the part of CORBA compliance. Hence, we design a new model of real-time object group platform that can support the real-time requirement without modifying the ORB. The structure of our real-time object group analyzed and defined the requirement about object management and real-time application service sides. And the role of the components of real-time object group is divided into 2 classes for reducing the side effect of interoperability between management and service. Also, we considered how to transparently express the parameters of real-time properties for clients and developers of server's service objects. If the expression of real-time parameters is transparent, then the developer can easily extend the real-time parameters simply and flexibly. Therefore, in this paper we defined the role of components of platform and described functions of each component and designed and then implemented the real-time object group platform. Finally, we showed the execution procedures of implemented our platform for verifying the functionality.

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Video Retrieval System supporting Adaptive Streaming Service (적응형 스트리밍 서비스를 지원하는 비디오 검색 시스템)

  • 이윤채;전형수;장옥배
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.1
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    • pp.1-12
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    • 2003
  • Recently, many researches into distributed processing on Internet, and multimedia data processing have been performed. Rapid and convenient multimedia services supplied with high quality and high speed are to be needed. In this paper, we design and implement clip-based video retrieval system on the Web enviroment in real-time. Our system consists of the content-based indexing system supporting convenient services for video content providers, and the Web-based retrieval system in order to make it easy and various information retrieval for users in the Web. Three important methods are used in the content-based indexing system, key frame extracting method by dividing video data, clip file creation method by clustering related information, and video database construction method by using clip unit. In Web-based retrieval system, retrieval method ny using a key word, two dimension browsing method of key frame, and real-time display method of the clip are used. In this paper, we design and implement the system that supports real-time display method of the clip are used. In this paper, we design and implement the system that supports real-time retrieval for video clips on Web environment and provides the multimedia service in stability. The proposed methods show a usefulness of video content providing, and provide an easy method for serching intented video content.

Building a Robust 3D Statistical Shape Model of the Mandible (견고한 3차원 하악골 통계 형상 모델 생성)

  • Yoo, Ji-Hyun;Hong, Helen
    • Journal of KIISE:Software and Applications
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    • v.35 no.2
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    • pp.118-127
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    • 2008
  • In this paper, we propose a method for construction of robust 3D statistical shape model in the mandible CT datasets. Our method consists of following four steps. First, we decompose a 3D input shape Into patches. Second, to generate a corresponding shape of a floating shape, all shapes in the training set are parameterized onto a disk similar to the patch topology. Third, we generate the corresponding shape by one-to-one mapping between the reference and the floating shapes. We solve the problem failed to generate the corresponding points near the patch boundary Finally, the corresponding shapes are aligned with the reference shape. Then statistical shape model is generated by principle component analysis. To evaluate the accuracy of our 3D statistical shape model of the mandible, we perform visual inspection and similarity measure using average distance difference between the floating and the corresponding shapes. In addition, we measure the compactness of statistical shape model using the modes of variation. Experimental results show that our 3D statistical shape model generated by the mandible CT datasets with various characteristics has a high similarity between the floating and corresponding shapes and is represented by the small number of modes.

Comparison of Partial Least Squares and Support Vector Machine for the Flash Point Prediction of Organic Compounds (유기물의 인화점 예측을 위한 부분최소자승법과 SVM의 비교)

  • Lee, Chang Jun;Ko, Jae Wook;Lee, Gibaek
    • Korean Chemical Engineering Research
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    • v.48 no.6
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    • pp.717-724
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    • 2010
  • The flash point is one of the most important physical properties used to determine the potential for fire and explosion hazards of flammable liquids. Despite the needs of the experimental flash point data for the design and construction of chemical plants, there is often a significant gap between the demands for the data and their availability. This study have built and compared two models of partial least squares(PLS) and support vector machine(SVM) to predict the experimental flash points of 893 organic compounds out of DIPPR 801. As the independent variables of the models, 65 functional groups were chosen based on the group contribution method that was oriented from the assumption that each fragment of a molecule contributes a certain amount to the value of its physical property, and the logarithm of molecular weight was added. The prediction errors calculated from cross-validation were employed to determine the optimal parameters of two models. And, an optimization technique should be used to get three parameters of SVM model. This work adopted particle swarm optimization that is one of heuristic optimization methods. As the selection of training data can affect the prediction performance, 100 data sets of randomly selected data were generated and tested. The PLS and SVM results of the average absolute errors for the whole data range from 13.86 K to 14.55 K and 7.44 K to 10.26 K, respectively, indicating that the predictive ability of the SVM is much superior than PLS.

CLINICOSTATISTICAL ANALYSIS OF SURGICAL FINDINGS IN CHRONIC OTITIS MEDIA (만성 중이염의 수술시 소견에 대한 임상통계적 관찰)

  • 최덕주;전병훈;민원식;함태영
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1987.05a
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    • pp.6-6
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    • 1987
  • 만성중이염은 현재 그 빈도가 줄어드는 추세에 있으나 아직도 이과 영역에서 큰 비중을 차지하는 질환이다. 또한 청력개선, 정상구조의 보존, 병변 제거의 목적을 위하여 대부분 수술적 요법이 필요하게 된다. 이에 저자들은 본 병원에서 시행한 만성 중이염 451예, 남자 238예, 여자 213예. 진주종성 중이염 170예, 비진주종성 중이염 273예에 대한 수술시 소견에 대한 임상 통계적 관찰을 한 바, 다음과 같은 결과를 얻었다. 1) 관찰대상을 술식별로 분류하면 진주종성 중이염과 비진주종성 중이염의 비가 $\circled1$ Myningoplasty ; 19.1% : 0%, $\circled2$ Tympanoplasty without mastoidectomy ; 34.5% : 14.4%, $\circled3$ Tympanoplasty with mastoidectomy ; 3.0% :12.1% 이었다. 2) 고막천공부위는, 진주종성 중이염과 비진주종성 중이염의 비가 변연부천공이 10.1% : 5.5%, 상고실천공이 38.8% : 1.4%, 중심부천증이 12.9% : 47.3%, 전천공이 32.5% : 39.6%, 고막유착이 5.6% : 6.2% 을 보였다. 3) 이소골의 상태는 진주종성중이염과 비진주종성 중이염의 비가, 모든 이소골의 손실은 26.6% : 4.3%, 모든 이소골이 정상에 가까운 예는 16.6% : 69.3%, 가장 병변이 심했던 침골 이상은 76.9% : 24.8% 를 보였다. 4) 중이강 점막소견은 진주종성 중이염과 비진주종성 중이염의 비가, 정상에 가까운 예가 16.7% : 47.0%, 병적 소견을 보인 예가 83.3% : 53.0% 이었다. 5) 진주종성 중이염과, 비진주종성 중이염에서의 안면신경관노출은 2.2% : 0.3%, 뇌막노출은 9.5% : 2.9%, 횡정맥동노출은 5.0% : 1.1%, 미로누공은 1.7% : 0% 이었다.lant, engineering service business can be said "The Software of Total Industry." Engineering service is what is called a higher business which offers specialized engineering know-how and experience. Engineering service compaines offer Its specialized knowledge and experience to government, industry and commerce. Whether the task is to modernize plant equipment, to design a building or to manage construction, an engineering company will develop and implement the most appropriate and cost effective solution. Clients use the engineering service of firm knowing that the engineer′s professional judgement is not influenced or biased by other commercial affiliations. While benefiting from the diverse experience that professional engineers can apply to a specific problem, government and industry also reduce the need for permanent in-house engineering staff. Engineering firms may be specialized or multi-disciplinary.도말표본에서와 같이 제 14 일 이전에는 호중구가, 그 이후에는 단핵구가 주종을 이루었다.>18.9dB

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SPARQL Query Processing System over Scalable Triple Data using SparkSQL Framework (SparQLing : SparkSQL 기반 대용량 트리플 데이터를 위한 SPARQL 질의 시스템 구축)

  • Jeon, MyungJoong;Hong, JinYoung;Park, YoungTack
    • Journal of KIISE
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    • v.43 no.4
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    • pp.450-459
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    • 2016
  • Every year, RDFS data tends further toward scalability; hence, the manner of SPARQL processing needs to be changed for fast query. The query processing method of SPARQL has been studied using a scalable distributed processing framework. Current studies indicate that the query engine based on the scalable distributed processing framework i.e., Hadoop(MapReduce) is not suitable for real-time processing because of the repetitive tasks; in addition, it is difficult to construct a query engine based on an In-memory Distributed Query engine, because distributed structure on the low-level is required to be considered. In this paper, we proposed a method to construct a query engine for improving the speed of the query process with the mass triple data. The query engine processes the query of SPARQL using the SparkSQL, which is an In-memory based, distributed query processing framework. SparkSQL is a high-level distributed query engine that facilitates existing SQL statement. In order to process the SPARQL query, after generating the Algebra Tree using Jena, the Algebra Tree is required to be translated to Spark Algebra Tree for application in the Spark system, and construction of the system that generated the SparkSQL query. Furthermore, we proposed the design of triple property table based on DataFrame for more efficient query processing in the Spark system. Finally, we verified the validity through comparative evaluation with the query engine, which is the existing distributed processing framework.

Towards Safety Based Design Procedure for Ships

  • Bakker, Marijn;Boonstra, Hotze;Engelhard, Wim;Daman, Bart
    • Journal of Ship and Ocean Technology
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    • v.5 no.3
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    • pp.1-13
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    • 2001
  • Present-day rules and regulations for the design and construction of ships are almost without exemption of a prescriptive and deterministic nature. Often it is argued that this situation is far from ideal; it does no right to the advances, which have been made during the past decades in engineering tools in marine technology, both in methodology and in computational power. Within IMO this has been realized for some time and has resulted in proposals to use Formal Safety Assessment(FSA) as a tool to improve and to modernize the rule making process. The present paper makes use of elements of the FSA methodology, but instead of working towards generic regulations or requirements, a Risk Assessment Approach, not unlike a 'safety case'; valid for a certain ship or type of ship is worked out. Delft University of Technology investigated the application of safely assessment procedures in ship design, in co-operation with Anthony Veder Shipowners and safety experts from Safely Service Center BV. The ship considered is a semi-pressurized-fully refrigerated LPG carrier. On the basis of the assumption that a major accident occurs, various accident, scenarios were considered and assessed, which would impair the safety of the carrier. In a so-called Risk Matrix, in which accident frequencies versus the consequence of the scenarios are depicted, the calculated risks all appeared lo be in the ALARP('as low as reasonable practicable') region. A number of design alternatives were compared, both on safety merits and cost-effectiveness. The experience gained with this scenario-based approach will be used to establish a set of general requirements for safety assessment techniques in ship design. In the view that assessment results will be most probably presented in a quasi-quantified manner, the requirements are concerned with uniformity of both the safety assessment. These requirements make it possible that valid comparison between various assessment studies can be made. Safety assessment, founded on these requirements, provides a validated and helpful source of data during the coming years, and provides naval architects and engineers with tools experience and data for safety assessment procedures in ship design. However a lot of effort has to be spent in order to make the methods applicable in day-to-day practice.

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A Study on Prevention of Accidents of Carbon Monoxide Leak from Gas Boilers (가스보일러 일산화탄소 누출사고 경감에 관한 연구)

  • Song, Jaechang;Kwon, Hweeung;Lee, Younghee;Moon, Il
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.277-281
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    • 2012
  • This work is concerned with a plan for preventing accidents of CO gas leak from gas boilers, involving the enforcement of installations of both CO alarm system and condensing boilers, and financial support of government grants. If amongst 1,460,000 beneficiaries of basic livelihood security, one million households in use of gas boilers receive 3-year support of 200,000 won, the difference of prices between common and condensing boilers, the government grants would be 2,000 billion won. If 3 million common householders are in 3-year support of 100,000 won, government grants would be 3,000 billion won. Therefore, 3-year grand total of government grants would be 5,000 billion won. Finance for government grants can be purveyed from energy saving; yearly 2,000 billion won of energy saving by enforcing to replace one million existing boilers with condensing boilers, leading to 2 trillion won of energy saving for 10 years. In this way, 6,000 billion won of 3-year grand total of government grants for CO alarm system and condensing boilers can be purveyed. The rest amount would be fundraised for energy savings. We claim that our proposal can make an achievement of more than 50% reduction of CO leak accidents during 10 years.