• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.827-832
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• 2002

The development of dedicated network management system is essential to meet the following conditions: the system must run the configuring and repair processing for the dedicated communication network, and can manage new next generation data dedicated communication network of various types. In general it is effective that the system is consisted of decentralized module to be accessible for business logic and datum to remote area. To solve these problems, a method is to use object-oriented design techniques. That is, it is to abstract reusability objects and make component module using the abstracted objects. In this paper, we propose a management system of dedicated communication network service using object-oriented design techniques which are UML(Unified Modeling Language).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.97-100
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• 2007

In order to overcome many defects in the current JPEG standard of still image compression, the new JPEG2000 standard has been development. The JPEG2000 standard is based on the principles of DWT and EBCOT Entropy Coding. EBCOT(Embedded block coding with optimized truncation) is the most important technology in the latest image-coding standard, JPEG2000. However, EBCOT occupies the highest computation time to operate bit-level processing. Therefore, many researches have achieved methods to minimize computation speed of EBCOT. Thus, this paper proposes the method of context-extraction that improves computational architecture. This paper proposes efficient context coding method. The proposed algorithm would apply to hard-wired JPEG2000 Encoder that is used for compression of high resolution image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.757-760
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• 2012

Cloud storage system that cloud computing providers provides large amounts of data storage and processing of cloud computing is a key component. Large vendors (such as Facebook, YouTube, Google) in the mass sending of data through the network quickly and easily share photos, videos, documents, etc. from heterogeneous devices, such as tablets, smartphones, and the data that is stored in the cloud storage using was approached. At time, growth and development of the globally data, the cloud storage business model emerging is getting. Analysis new network storage cloud storage services concepts and technologies, including data manipulation, storage virtualization, data replication and duplication, security, cloud computing core.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1964-1980
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• 2016

This paper presents a new simplified harmonics extraction algorithm based on the synchronous reference frame (SRF) for an indirect current controlled (ICC) three-level neutral point diode clamped (NPC) inverter-based shunt active power filter (SAPF). The shunt APF is widely accepted as one of the most effective current harmonics mitigation tools due to its superior adaptability in dynamic state conditions. In its controller, the SRF algorithm which is derived based on the direct-quadrature (DQ) theory has played a significant role as a harmonics extraction algorithm due to its simple implementation features. However, it suffers from significant delays due to its dependency on a numerical filter and unnecessary computation workloads. Moreover, the algorithm is mostly implemented for the direct current controlled (DCC) based SAPF which operates based on a non-sinusoidal reference current. This degrades the mitigation performances since the DCC based operation does not possess exact information on the actual source current which suffers from switching ripples problems. Therefore, three major improvements are introduced which include the development of a mathematical based fundamental component identifier to replace the numerical filter, the removal of redundant features, and the generation of a sinusoidal reference current. The proposed algorithm is developed and evaluated in MATLAB / Simulink. A laboratory prototype utilizing a TMS320F28335 digital signal processor (DSP) is also implemented to validate effectiveness of the proposed algorithm. Both simulation and experimental results are presented. They show significant improvements in terms of total harmonic distortion (THD) and dynamic response when compared to a conventional SRF algorithm.

• Journal of Construction Engineering and Project Management
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• v.3 no.4
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• pp.12-19
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• 2013

Green Frame is an environmentally friendly column-beam system composed of composite PC members that can increase buildings' life spans while reducing resource consumption. Typically, connections of PC and RC columns occur at the boundaries of each floor, which is at the upper section of slabs, causing the boundary of each floor to generate the maximum moment. Although it is not optimal in terms of structural safety to connect members at a location where the moment is high, this approach is highly adopted due to its constructability. We propose that a superior approach that employs the concept of connecting columns at the low bending moment zone can be applied to quickly and safely install green columns, the main structural members of Green Frame. Connection of green columns at the low bending moment zone can be classified into three techniques, depending on the method of reinforcing the joints, which have different connection characteristics and construction methods. Research is needed to compare the features of each method of reinforcing the joints so that the most appropriate column connection method can be chosen for the site conditions. This study aims to confirm the structural safety of the connection component at the low bending moment zone and to compare and analyze the construction duration, unit price, quality and safety performance of each column connection method. The study results are anticipated to activate the use of composite precast concrete and to be used as development data in the future.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.321-326
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• 2009

A simple measuring device is proposed, and its performance is examined in an adsorption process separating a gas mixture. The sensor is made of a quartz crystal resonator and solid adsorbent to detect the target component. Micro-particle carbon cryogel(MCC) is utilized as the adsorbent, and the gas mixture of air and i-butane are separated in a column containing bamboo activated carbon. Two devices are placed at the inlet and outlet of the column. The measurements are compared with those of GC outcome to prove the measurements are effective. The experimentally proved system is simple and capable to be implemented in an in-line system with on-line measurement.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1063-1070
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• 2002

With a remarkable growth and expansion of Internet, the security issues emerged from intrusions and attacks such as computer viruses, denial of services and hackings to destroy information have been considered as serious threats for Internet and the private networks. To protect networks from intrusions and attacks, many vendors have developed various security systems such as firewalls and intrusion detection systems. However, managing these systems individually demands too much work and high cost. Thus, integrated and autonomous security management for various security products has become more important. In this paper, we present the architecture of the WISMSF (Web-based Integrated Security Management System for Firewalls) and the merits of centralized approach for managing heterogeneous firewalls and implement the prototype of the central policy database that is a component of the WISMSF engine. The WISMSF engine supports an integrated view for policies, the integrity of polities and the easy recovery and addition of policies. And also, we define the policy conflicts of WISMSF and present the policy recovery process to support to the policies consistence.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.106-111
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• 1999

To investigate the effects of planting density and nitrogen level on growth and yield potential of newly bred heavy panicle japonica rice with large grain (Iksan 435 and Iksan 438) or many spikelets per panicle(HR14022-21-8-4 and HR14022-21-8-6), four heavy panicle type rices and two many panicle type rices(Dongjinbyeo and Donganbyeo) as the checks were planted under standard planting density (30$\times$15 cm) and dense planting density (15$\times$15 cm) with two nitrogen levels of standard nitrogen level(110 kg h $a^{-1}$) and heavy nitrogen level(165 kg h $a^{-1}$). Effective tiller rate decreased in dense planting or heavy nitrogen, when compared to standard nitrogen and planting, while leaf area index and to dry weight increased in dense planting or heavy nitrogen. Tiller numbers and panicle numbers were more increased by dense planting than heavy nitrogen, whereas spikelet numbers were more increased by heavy nitrogen than dense planting. Ripened grain ratio was slightly lower only in dense planting. 1,000 grain weight in brown rice was not significantly different in dense planting or heavy nitrogen. Milled rice yield was highest in heavy nitrogen with standard planting for heavy panicle type rice, while yield for many panicle type rice was highest in heavy nitrogen with dense planting, suggesting that many panicle type rice possesses higher adapt-ability for dense planting than heavy panicle type rice. Path coefficient analysis revealed that top dry weight, spikelet number and grain weight were the greatest positive contributors to yield, whereas tiller number was negative to yield.d.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.107-113
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• 2010

The object of this research is to conform of practicable possibility and recycling of producing junk after citrus fruits is processed. With extracting d-limonene oil that have 70~90% a component of oil out of junk citrus peel, making certain the about 12000ppm concentration of it. Limonene derived from citrus in jeju using conventional synthetic detergents can be replaced with the development of environmentally friendly natural detergent investigated the possibility. Mostly due to ocean dumping, disposal and cause environmental problems by recycling natural citrus cleaner alternative to the research conducted on the possibility. Cleaning efficiency with temperature did not affect the largest concentrations were able to identify the difference between cleaning efficiency. At least 10% of the d-limonene oil could be from the cleaning performance, increasing the concentration of the cleaning efficiency was increased in size. Ultrasonic is very high removal efficiency under the conditions shown in the cause of pure self-generated ultrasonic cleaning power as co-effects of d-limonene oil appears to chemical cleaning effect of ultrasonic cavitation occurs in the physical cleaning effect due to a combination of synergistic stability is maximized by low concentrations of d-limonene oil in a short time showed an excellent cleaning ability. Having the ability of cleaning at the same time, considering the side recycling in the junk citrus peels reflects possibility of basic materials utility eco-friendly in the skin soap, bath soap, cosmetics etc, through ability of exclusion a contaminant in based cleaning effect(EC) it can prospect substitution effect environmentally in the pre existence synthetic detergents.