• International Commerce and Information Review
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• v.15 no.2
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• pp.129-162
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• 2013

The purpose of this work is to explore the role of international entrepreneurship(IE) in explaining internationalization process of Korean ventures and to structure the model of IE with the logics of effectuation. The internationalization of entrepreneurial company is regarded as the realization of entrepreneurship which find out and use opportunities across borders in this point of view, and the realization process gets more realistic and applicable to the internationalization of ventures by effectuation. So we constructed the new concepts of the generating-internationalization-outcome capability(GIOC), which is the effectual capability allowing ventures to go international despite their lack of internal resources and experiences. Its sub-capabilities of GIOC are extemporaneous coping capability, perform-resource-in-hand capability and network-use capability. The empirical analyses of the relations among the capabilities and the performances of internationalization are performed in order to prove the rationale of the model, which provides finally significant evidences of the relationships. The key contribution of this study is that it highlights the important role of IE in internationalization of ventures and shows the possible role of effectuation in explaining the realization process of IE.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2C
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• pp.95-112
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• 2007

Spatial Multiplexing techniques, which is a kind of Multiple antenna techniques, provide high data transmission rate by transmitting independent data at different transmit antenna with the same spectral resource. OFDM (Orthogonal Frequency Division Multiplexing) is applied to MIMO (Multiple-Input Multiple-Output) system to combat ISI (Inter-Symbol Interference) and frequency selective fading channel, which degrade MIMO system performance. But, orthogonality between subcarriers of OFDM can't be guaranteed under high-mobility condition. As a result, severe performance degradation due to ICI is induced. In this paper, both ICI and CAI (Co-Antenna Interference) which occurs due to correlation between multiple antennas, and performance degradation due to both ICI and CAI are analyzed. In addition to the proposed CIR (Channel Impulse Response) estimation method for avoiding loss in data transmission rate, HIC (Hybrid Interference Cancellation) approach for guaranteeing QoS of MIMO-OFDM receiver is proposed. We observe the results on analytical performance degradation due to both ICI & CAI are coincide with the simulation results and performance improvement due to HIC are also verified by simulation under SCM-E Sub-urban Macro MIMO channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.80-90
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• 1996

The efficienty of ATM is based on the statical multiplexing of fixed-length packets, which are called cells. The most important technical point for realizing ATM switching network is an arrangement of the buffers and switches. Current most ATM switching networks are being achieved by using the switching modules based on the unit switch of $8{\times}8$ 150Mb/s or $16{\times}16$ 150Mb/s, the unit switch of $32{\times}32$150Mb/s for a large scale system is under study in many countries. In this paper, we proposed a new $32{\times}32$(4.9Gb/s throughput) ATM switch using Shared buffer memory switch which provides superior traffic characteristics in the cell loss, delay and throughput performance and easy LSI(Large Scale Integrated circuit). We analytically estimated and simulated by computer the buffer size into it. We also proposed the configuration of the large capacity ATM switching network($M{\times}M$.M>1,000) consisting of multistage to improve the link speed by non-blocking.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.9
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• pp.652-662
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• 2001

A WDM/SCM multiple access protocol suitable for optical double star networks is proposed. A node-grouping scheme is employed in the protocol, which is accomplished by connecting some nodes through passive star sub-hubs forming a group. The resulting multiple groups in a network are then connected through a central passive star hub resulting in a passive double star network. Each group is pre-assigned a WDM channel as its home channel, and SCM channels are used to identify the packet reception at each node. [n the proposed protocol, the average packet delay is remarkably reduced since the frame consists of the number of groups rather than the number of network nodes. Furthermore, additional reduction of the average packet delay is achieved by limiting the propagation paths of control packets to the roundtrip between source nodes and sub-hub using a double star network. It is shown in the performance evaluations using analytic and simulation model that the proposed protocol has the advantages of the higher channel utilization and excellent network throughput and average packet delay characteristic.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.817-830
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• 2015

This study performed prediction of extreme rainfall uncertainty and its frequency analysis based on climate change scenarios by Coupled Model Intercomparison Project Phase 5 (CMIP5) for the selected nine-General Circulation Models (GCMs) in the near future (2011-2040) over the Korean Peninsula (KP). We analysed uncertainty of scenarios by multiple model ensemble (MME) technique using non-parametric quantile mapping method and bias correction method in the basin scale of the KP. During the near future, the extreme rainfall shows a significant gradually increasing tendency with the annual variability and uncertainty of extreme ainfall in the RCP4.5, and RCP8.5 scenarios. In addition to the probability rainfall frequency (such as 50 and 100-year return periods) has increased by 4.2% to 10.9% during the near future in 2040. Therefore, in the longer-term water resources master plan, based on the various climate change scenarios (such as CMIP5 GCMs) and its uncertainty can be considered for utilizing of the support tool for decision-makers in water-related disasters management.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.11a
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• pp.358-374
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• 2002

최근 빈번하게 발생하고 있는 사우나 등의 열을 방사하는 도크내에서 발생하는 화재사고는 다중이용업소를 이용하는 불특정한 사람들의 생명을 위협하고 있는 수준에 도달하고 있다. 특히 이런 시설의 화재는 화재발생 후에 소방대에 의한 진압에만 치중하고 있어 향후 계속하여 화재가 발생할 우려가 큼에도 불구하고 착화원인을 규명하는데 소홀히 하고있다. 특히 현장감식에 의한 육안조사만을 실시하여 화재원인을 추정하거나 설정하는 경우가 대부분이라 근본적인 대책을 세우지 못하고 있다. 따라서 본 연구에서는 육안조사 등에 의하여 설정한 착화원인을 과학적인 분석법 즉, EU국가에서 널리 사용하는 CFD(컴퓨터수치해석)시뮬레이션 S/W를 사용하여 연소모델링에 의한 검증조사기법을 적용하여 원인을 검증하는데 사용하여 국내화재조사기술의 과학화를 시도하였다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.96-106
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• 2009

Extending the scale of the distributed processing in a single Ethernet cluster is physically restricted by maximum ports per switch. This paper presents an implementation of MPI-based multicluster consisting of multiple Ethernet switches for extending the scale of distributed processing, and a asymptotical analysis for communication overhead through execution-time analysis model. To determine an optimum task partitioning, we analyzed the processing time for various partitioning schemes, and AAP(accumulator array partitioning) scheme was finally chosen to minimize the overall communication overhead. The scope of data partitioned in AAP was modified to fit for incremented nodes, and suitable load balancing algorithm was implemented. We tried to alleviate the communication overhead through exploiting the pipelined broadcast and flat-tree based result gathering, and overlapping of the communication and the computation time. We used the linear pipeline broadcast to reduce the communication overhead in intercluster which is interconnected by a single link. Experimental results shows nearly linear speedup by the proposed parallel distributed GHT implemented on MPI-based Ethernet multicluster with four 100Mbps Ethernet switches and up to 128 nodes of Pentium PC.

• Journal of the Korean Geographical Society
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• v.44 no.3
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• pp.301-322
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• 2009

This paper is an attempt to explore semiotic representations of subway space as the urban machine space of local mobility in terms of space, time and place. For this, the second section of the paper reviews the contours of the urban space of mobility in terms of 'machine space', 'non-place' and 'cognitive map'. The third section interprets the sings of 'spatial' and 'temporal' representations of subway space in Daegu, and suggests the implications of the semiotic representations. It is uncovered that various sign-scapes which coexist in the subway space in coordinated or contradictory ways product the space into multiple and complex techno-social spaces. That is, the spatio-temporal representations of the subway space form the space of 'non-place' on the one hand and the space of 'place' on the other hand, and involve the spatialization of 'memory' on the one hand and the spatialization of 'forgetting' on the other hand. Thus, the subway space should be regarded to be not only the space of 'mobility' which people move in and through, but also the space of 'identity' which has effects on the ways for them to see the machine space and its urban space.

• Composites Research
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• v.26 no.6
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• pp.363-372
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• 2013

Numerical simulation for Resin Transfer Molding manufacturing process is attempted by using the eXtended Finite Element Method (XFEM) combined with the level set method. XFEM allows to obtaining a good numerical precision of the pressure near the resin flow front, where its gradient is discontinuous. The enriched shape functions of XFEM are derived by using the level set values so as to correctly describe the interpolation with the resin flow front. In addition, the level set method is used to transport the resin flow front at each time step during the mold filling. The level set values are calculated by an implicit characteristic Galerkin FEM. The multi-frontal solver of IPSAP is adopted to solve the system. This work is validated by comparing the obtained results with analytic solutions. Moreover, a localization method of XFEM and level set method is proposed to increase the computing efficiency. The computation domain is reduced to the small region near the resin flow front. Therefore, the total computing time is strongly reduced by it. The efficiency test is made with a simple channel flow model. Several application examples are analyzed to demonstrate ability of this method.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.86-91
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• 2014

In the field of shipbuilding and marine, electrical power system is that each of the distributed bus bars is connected electrically. In this way, it would be appropriate to recognize as grid-connecting rather than the redundant bus. Short-circuit capacity of the electric power system will be increased proportionally which is due to the addition of the bus. The increase of short-circuit capacity needs high initial cost associated with equipment and can generate the blackout when the equipment with a physically connected to the bus occurs the electric failure. In order to solve these problems, marine electrical power system in which current limiting reactor has been applied is classified according to the network topology, bus network, star network and ring network. And short circuit analysis for each network is performed by the fault types. The results are presented pros and cons compared to each other.