• Journal of Embryo Transfer
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• v.29 no.1
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• pp.1-5
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• 2014

Recent 2 decades, including in vitro maturation (IVM), assisted reproductive technologies (ARTs) achieved noteworthy development. However the efficiency of ARTs with in vitro matured oocytes is still lower than that with in vivo oocytes. To overcome those limitations, many researchers attempted to adapt co-culture system during IVM and consequently maturation efficiency has been increased. The beneficial effects of applying co-culture system is contemplated base on communication and interaction between various somatic cells and oocytes, achievement of paracrine factors, and spatial effects of extracellular matrix (ECM) from somatic cell surface. The understanding of co-culture system can provide some information to narrow the gap between in vitro and in vivo. Here we will review current studies about issues for understanding cu-culture system with various somatic cells to improve in vitro maturation microenvironment and provide bird view and strategies for further studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2395-2410
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• 2013

Many telecommunication operators around the world have multiple networks. The networks run by each operator are always of different generations, such as 2G and 3G or even 4G systems. Each system has unique characters and specified requirements for optimal operation. It brings about resource allocation problem among these networks for the operator, because the budget of each operator is limited. However, the evaluation of resource allocation among various networks under each operator is missing for long, not to mention resource allocation optimization. The operators are dying for an algorithm to end their blind resource allocation, and the Resource Allocation Optimization Algorithm for Multi-network Operator (RAOAMO) proposed in this paper is what the operators want. RAOAMO evaluates and optimizes resource allocation in the view of overall cost for each operator. It outputs a resource distribution target and corresponding optimization suggestion. Evaluation results show that RAOAMO helps operator save overall cost in various cases.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.752-761
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• 2016

Tactical Multiband Multirole radio(TMMR) has been developed and under some official testings now. Our army wants TMMR to be installed in Ground Fighting Vehicles(GFVs) and be incorporated with their Battlefield Management System(BMS). Also, BMS with TMMR should communicate with BMS on FM radio which is currently under use in most of GFVs. To achieve such goals, some significant changes should be made into the present BMS and in this paper, several considerations will be presented in the both sides of hardware and software point of view.

• Journal of Welding and Joining
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• v.13 no.1
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• pp.127-137
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• 1995

The possibility of new GMAW process using economic shielding gases including CO$_{2}$ gas was investigated on the effect of shielding gas on weldabilty. In the optimum welding condition using 600A power source, FCAW process showed low depositions rate, 114 g/min at 300A, but new GMAW using other mixed shielding gases exhibited high deposition rate, 208-224 g/min at 450A. TIME gas, Ar+CO$_{2}$ gas and Ar+CO$_{2}$+O$_{2}$ gas as a shielding gas were able to be used to the very high welding current(450A), moreover TIME gas and Ar+CO$_{2}$ gas showed the highest arc stability among shielding gases studied in this experiments. The weld penetration was performed by axial spray transfer mode of weld droplet. On the basis of workability, weldability and economic point of view, Ar mixture (80%Ar+20%CO$_{2}$) gas was recommended as a shielding gas for the development and application of new GMAW process. This shielding gas showed the low spatter, good weld quality, stable arc and low cost at the region of high welding current.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.991-996
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• 2004

Plastics are widely used in industry, because they are light, easily manufactured, and have high specific strength. And many researches to increase the strengths and to reduce the price are being conducted at now. One of these researches is concerning to additives. Foaming techniques are used to endow insulation properties, to improve specific strength, or reduce the material cost. Due to their unique properties, foamed plastics are applied to refrigerator, pipe, and insulators. Micro-cellular foaming is the latest foaming technique that was invented at 1980 in MIT. It is known that many tiny small cells are generated in the polymer matrices and micro-cellular foamed plastics show relatively high specific strength. We investigated the role of CaCO3 which is one of the most widely used additives in plastics industry as an additive for nucleation in view of cell morphology. CaCO3 used in this paper was treated to increase the dispersibility and to lower the density, so it has many pores at his body. Two experiments were conducted, in order to check the role of an additive for nucleation. One is compound-ability and the other one is role of nucleation agents.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.71-79
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• 2009

The world-wide ship construction market is forecast that the considerable portion of shipbuilding and oceanic plant industry will be transferred consequently in China after 5 or 10 years. This point of view where the Korean ship construction industry seizes the initiative from the world-wide ship construction/oceanic field, we must cultivate technical power of base technology, and focus our interests on the development of core parts. In this study, our proprietary remotely operated valve actuator system with power line technology was developed to enhance the installation and commissioning process by our own technology. This paper describes the new design and functions of the remotely operated valve system for shipbuilding and offshore market especially for FPSO.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.380-385
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• 2012

This paper contains the optimized M2M technology, and the information of production resource of 4M, which understanding the roles and functions of M2M Device, and the explanation of its effectiveness, and the information of optimized M2M Device in IT convergence point of view. In addition, this content also points out the optimized M2M Device, analyzes and collects various type of management information which emphasizes the need for a common platform's were Middleware, and Auto-Configuration, WebLine Monitoring, WebService through the functionality of an integrated management information supports the productions by digitizing the information with standardized data for management efficiency.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.170-172
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• 1998

In the future, it is expected that a fault-current of 345kV power system is beyond 60kA and stability and reliability in transmission system will be more important. From these points of view, we needed a development of a circuit breaker having ability of breaking a large fault current, more than 60kA. This paper describe the specification and history of a development on 362kV 63kA 8000A GCB(Gas insulated Circuit Breaker) of which we completed a development. A development of this GCB will contribute to improve the technique to design and make GCB, and the stability and reliability of power system in our country.

• Journal of Ship and Ocean Technology
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• v.12 no.1
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• pp.35-44
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• 2008

As arctic energy resource is attracting public attention, arctic shipping market will also be growing in large as expected to increase in LNG trade from Arctic area to the western countries by shipping. During the voyages through such routes, collision with icebergs may be possible. In the present report, ice collision analyses are carried out from a practical point of view to verify the safety of hull structural strength of LNG carriers equipped with GTT $MKIII^{TM}$ membrane type cargo containment system. From the results of collision analyses and the operation-friendly design concept of no-repairing of cargo containment system, a safe operating envelope against ice collision is proposed for LNG carriers of membrane type cargo containment system. Based on the currently proposed safety criteria, it is concluded that LNG carriers with membrane tank type can operate safely with regard to the integrity of CCS in regions where collision between LNG carrier and iceberg is expected.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.12
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• pp.3836-3854
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• 2022

The student group division is benefit for universities to do the student management based on the group profile. With the widespread use of student smart cards on campus, especially where students living in campus residence halls, students' daily activities on campus are recorded with information such as smart card swiping time and location. Therefore, it is feasible to depict the students with the daily activity data and accordingly group students based on objective measuring from their campus behavior with some regular student attributions collected in the management system. However, it is challenge in feature representation due to diverse forms of the student data. To effectively and comprehensively represent students' behaviors for further student group division, we proposed to adopt activity data from student smart cards and student attributes as input data with taking account of activity and attribution relationship types from different perspective. Specially, we propose a novel student group division method based on a multi-view student attribute heterogeneous information network (MSA-HIN). The network nodes in our proposed MSA-HIN represent students with their multi-dimensional attribute information. Meanwhile, the edges are constructed to characterize student different relationships, such as co-major, co-occurrence, and co-borrowing books. Based on the MSA-HIN, embedded representations of students are learned and a deep graph cluster algorithm is applied to divide students into groups. Comparative experiments have been done on a real-life campus dataset collected from a university. The experimental results demonstrate that our method can effectively reveal the variability of student attributes and relationships and accordingly achieves the best clustering results for group division.