• Geomechanics and Engineering
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• v.9 no.5
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• pp.645-667
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• 2015

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

• Structural Engineering and Mechanics
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• v.29 no.2
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• pp.155-169
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• 2008

A MOM-based algorithm (MOMA) has been developed for moving force identification from dynamic responses of bridge in the companion paper. This paper further evaluates and investigates the properties of the developed MOMA by experiment in laboratory. A simply supported bridge model and a few vehicle models were designed and constructed in laboratory. A series of experiments have then been conducted for moving force identification. The bending moment and acceleration responses at several measurement stations of the bridge model are simultaneously measured when the model vehicle moves across the bridge deck at different speeds. In order to compare with the existing time domain method (TDM), the best method for moving force identification to date, a carefully comparative study scheme was planned and conducted, which includes considering the effect of a few main parameters, such as basis function terms, mode number involved in the identification calculation, measurement stations, executive CPU time, Nyquist fraction of digital filter, and two different solutions to the ill-posed system equation of moving force identification. It was observed that the MOMA has many good properties same as the TDM, but its CPU execution time is just less than one tenth of the TDM, which indicates an achievement in which the MOMA can be used directly for real-time analysis of moving force identification in field.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.9-17
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• 2013

This paper presents the design of the educational router system. This system is designed and implemented to support network configuration and embedded programming technology of the user on Internet. Not only Static routing protocol but also a kind of dynamic routing protocols such as OSPF and RIP and firewall have been programmed for education based on ethernet interface. ADS 1.2 as debugging environment, uC/OS-ii as RTOS and C language as development language are used. The educational procedures is compile, loading of static routing protocol, a kind of dynamic routing protocols such as OSPF and RIP and firewall program already supplied. Thereafter the verification is checked by using "ping" test to allow for demo operation such as hands-on training procedure. Finally programming procedure similar with demo operation of static routing protocol, a kind of dynamic routing protocols such as OSPF and RIP and packet filtering function is educated step by step.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.6
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• pp.195-202
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• 2005

An adaptive segmentation algorithm is used to efficiently target decisions in local non-stationary images. Until now, several adaptive approaches have been proposed as a method of segmentation. However, they can't be directly used for radar target detection because a radar signal has different characteristics from general images. Generally, a histogram of radar signal shows that targets have a relatively small number of frequency functions compared to the background and distribution of background, which have several shapes as the environment changes. In this paper, we propose an adaptive segmentation algorithm using a histogram chord which is a right-down line from maximum pick of frequency function. The proposed method provides thresholds which are optimum for several radar environments because the used chord for threshold search is not significantly effected by interference conditions. Simulation results show that the proposed method is superior to the traditional algorithms, global threshold method and distribution median method, with respect to detection performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.109-113
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• 2011

Recently, according to the development of ubiquitous computing, the u-GIS which not only used in u-Transport, u-Care, u-Fun, u-Green, u-Business, u-Government, and u-City but also used to provides various spatial information such as the location of user is being the core technology of the ubiquitous computing environment. In this paper, we implemented an mobile spatio-temporal Query Processing Systems for handling the Spatio-Temporal Data in mobile equipment.The mobile spatio-temporal Query Processing Systems provides the spatio-temporal data type and the spatio-temporal operator that is expanded by the spatial data type and the spatial operator from OepenGIS "Simple Feature Specification for SQL". It supports arithmetic coding compression techniques that is considered with a spatio-temporal data specific character. It also provides the function of data cashing for improving the importation and exportation of the spatio-temporal data between a embedded spatio-temporal DBMS and u-GIS server.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.3
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• pp.9-18
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• 2002

Landscape, the land mosaics, is combined with human and natural environment. Landuse and landcover changes are an important factor that changes structure and function of regional landscape. In this study, the changes of landcover and landscape structures are examined in Kyongsan between 1985 and 1997, using Landsat TM images and landscape indices. The results of this study are as follows; First, according to the classification of landcover, forest and agriculture areas have decreased as a result of urban expansion. Second, forest fragmentation has been brought by development; So forest healthiness has weakened. It is proved that urban expansion has happened in agriculture land. Third, a variety of landuse types around forest have changed from agriculture-oriented types to the ones mixed with urban and agriculture areas between 1985 and 1997.

• Archives of design research
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• v.15 no.3
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• pp.115-126
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• 2002

The occupational execution technique and the ability of people has been changed along with the change of thinking and the development of complicated social structure. The needs of learner's self-controlled learning system is arise to increase the occupational execution technique and adaptation in such a changing social environment. To meet these needs, we must develop systematic approach on the module-type educational material system. The purpose of this study lies on developing the module-type educational material system and its application in aspects of occupational execution ability. Based on the job analysis of advertising design, 1 analyze the learning ability for the occupational execution and abstract knowledge, function, attitude from each learning category of each learning ability. All these processes are the basis of developing the module-type educational material system. and the system will be appreciated in many other fields not only on advertising design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.713-718
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• 2014

DC urban railway power system consists of DC power network and AC power network. The DC power network supplies electric power to railway vehicles and the AC power network supplies electric power to station electric equipment. Recently, because of power consumption reduction and peak load shaving, intelligent measurement of regenerative energy and renewable energy adapted on DC urban railway is required. For this reason, DC smart metering system for DC power network shall be developed. Therefore, in this paper, DC voltage sensor, current sensor, and DC smart meter were developed and evaluated by performance test. DC voltage sensor was developed for measuring standard voltage range of DC urban railway, and DC current sensor was developed as hall effect split core type in order to install in existing system. DC smart meter possesses function of general intelligent electric power meter, such as measuring electricity and wireless communication etc. And, DC voltage sensor showed average 0.17% of measuring error for 2,000V/50mA, and current sensor showed average 0.21% of measuring error for ${\pm}2,000V/{\pm}4V$ in performance test. Also DC smart meter showed maximum 0.92% of measuring error for output of voltage sensor and current sensor. In similar environment for real DC power network, measuring error rate was under 0.5%. In conclusion, accuracy of DC smart metering system was confirmed by performance test, and more detailed performance will be verified by further real operation DC urban railway line test.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.119-132
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• 2012

Biodiversity is a key element of ecosystem of which function provides essential product and service in human life. In the course since development projects often causes damages to biodiversity, environmental impact assessment technique must be capable of accurately assessing potential impact from flora and fauna and to entire ecosystem. Korea needs improvement of its assessment technique that is compatible with Korean environmental regulatory standard that is generally stricter than that of most countries. This study attempts to explore both domestic and overseas biodiversity assessment techniques and analyze each stage of environmental impact assessment. The data is collected from numbers of literatures selected by navigating both domestic and overseas literature database with certain keywords. Among the 44 selected papers, overseas publications outnumber those of domestics, and there are more researches on assessment methodology of biodiversity than assessment tool and model. In terms of environmental impact assessment, the number of papers on environmental impact forecast exceeds the numbers of papers on current state of environment and the impact minimizing solution. Therefore, contents and trends of those researches in the different stages of environmental impact assessment discussed in this paper not only suggest potential impact on biodiversity and minimization solutions in detail, but is also a valuable resource particularly for biodiversity relevant environmental assessment technique improvement in Korea. Proposing of a new direction of improvement in biodiversity assessment techniques makes this study significant, and further research for preservation of biodiversity should follow up to provide an improvement scheme for biodiversity assessment techniques in the future.

• Korean Institute of Interior Design Journal
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• v.25 no.2
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• pp.131-142
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• 2016

Rapid economic development has played a big role in the formation of the values of pluralism. On that account, the importance of leisure life has grown substantially, Such phenomenon has allowed people to travel more frequently. Hence, there has been a growing demand for accommodation. In particular, the number of design hotels with a stylish design has grown exponentially as compared with the conventional standardized chain hotels. As a result, a variety of objets have been utilized in hotel spaces for establishing a differentiated formativeness and offering a visual stimulus to users. An objet refers to an object of symbolic function. That is to say, it serves to increase cultural values by approaching arts in an ordinary environment. Distinctive objets are mainly expressed as new ideas by the emerging designers in Europe. In particular, Marcel Wanders designs hotel spaces on the basis of the emotional meaning and story of objets, thereby showing interesting elements. He brings human stories into a design by leveraging the expressional characteristics of an objet, such as the place, fantasy and story-telling, in hotel interior spaces. This allows users, who reject the stereotypes of modern functionalism, to have exotic memories by stimulating their instinctive senses. Furthermore, this can complete users as a part of an artwork by creating a huge artwork on the basis of hotel interior spaces. In this regard, I hope that the expressional characteristics appeared in the hotel interior spaces of Marcel Wanders can be utilized as preliminary data for planning design hotels in the future.