• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1261-1266
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• 2009

In this paper, triple band mobile chip antenna for DCS(1.71${\sim}$1.88GHz) / PCS(1.75${\sim}$1.87GHz) / UPCS(1.8S${\sim}$1.99GHz) on PCB Layout is designed. To analyze the characteristics of the designed antenna, we used commerical simulation tool(HFSS). Triple and wide band characteristic could be realized the measured bandwidth(V.S.W.R<2.0) of the designed antenna operated in 1.71GHz${\sim}$1.99GHz. The size of the designed antenna is about 19mm${\times}$4mm${\times}$1.6mm, narrow bandwidth which is a defect of chip antenna is improved. And its experimental results were a good agreement with simulation performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1073-1083
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• 2015

As an empirical study focused on how transactive memory concept influence the four processes of knowledge growth, this study aimed at explaining the function of transactive memory in the dynamic process of knowledge growth. To verify the research model, this study carried out a path analysis of 130 team memebers and as a result, part of the team transactive memory measurements does affect the knowledge growth. Consequentially, transactive memory especially based on team level, is relevant with knowledge growth. According to team level, this study targeted at the team members, and by adopting the team transactive memory concept in Cognitive Psycology, theoretically explained and analysed how to approach personal knowledge in internal organizations. To accelerate the knowledge process, the work should be modified collaboratively by trusting the team members' duty relations more than specialized knowledge. Furthermore, managers had better assign team members the work where they can make the most of their personal knowledge, and this study presented that the whole team performance could be improved by doing that.

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.624-640
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• 2004

Recently, with the rapid development of location-based techniques, index structures to efficiently manage moving objects have been required. In this paper, we propose a new spatio-temporal index structure that supports a future position retrieval and minimizes a update cost. The proposed index structure combines an assistant index structure that directly accesses current positions of moving objects with KDB-tree that is a space partitioning access method. The internal node in our proposed index structure keeps time parameters in order to support the future position retrieval and to minimize a update cost. Moreover, we propose new update and split methods to maximize the space utilization and the search performance. We perform various experiments to show that our proposed index structure outperforms the existing index structure.

• KIISE Transactions on Computing Practices
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• v.21 no.7
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• pp.488-493
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• 2015

An AddSIM(Adaptive distributed and parallel Simulation environment for Interoperable and reusable Models) is an integrated engagement simulation environment with high-resolution weapon system models for estimation and analysis of their performance and effectiveness. AddSIM can simultaneously handle the continuous dynamical system models based on continuous time, and command, control(C2) and network system models based on a discrete event. To accommodate legacies based on DEVS(Discrete Event System Specification) modeling, DEVS legacies must first be converted into AddSIM models. This paper describes how to implement DEVS models on AddSIM. In this study a method of mapping from hierarchical DEVS models to AddSIM players was developed: The hierarchical DEVS model should be flattened into a one layered model and four DEVS functions of the model, external transition, internal transition, output and time advance, should be mapped into functions of the AddSIM player.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1402-1408
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• 2013

Document managements are very important in internal communication for good performance on projects. In case of small scale projects, the document management criteria often have very different from each of the cooperation departments and changes of document structure of work process are frequent over a project period. In this thesis, we propose a monitoring system of document management which is based on P2P(Peer-to-Peer). The proposed monitoring system of document management, which is based on P2P, makes up for time limits and a specific work process in small scale project groups. It can be managed focusing on work process and can monitor effectively the status of creations, sharing and distributions of documents. We can be installed at a low cost by using P2P in a small scale project.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.4
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• pp.177-185
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• 2005

NAND-type flash memory is becoming increasingly popular as a large data storage for mobile computing devices. Since flash memory is an order of magnitude more expensive than magnetic disks, data compression can be effectively used in managing flash memory based storage systems. However, compressed data management in NAND-type flash memory is challenging because it supports only page-based I/Os. For example, when the size of compressed data is smaller than the page size. internal fragmentation occurs and this degrades the effectiveness of compression seriously. In this paper, we present an efficient flash compression layer (FCL) for NAND-type flash memory which stores several small compressed pages into one physical page by using a write buffer Based on prototype implementation and simulation studies, we show that the proposed scheme offers the storage of flash memory more than $140\%$ of its original size and expands the write bandwidth significantly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.1-9
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• 2007

The performance of the small scale cyclone incinerate system (100kg/hr) to process the sewage sludge containing high moisture is evaluated. The incinerate system design is based on properties of the domestic sewage sludge. The combustion characteristics of the incinerate system is tested and analyzed with the various operation conditions of the moisture level, the sludge feed rate and the auxiliary fuel feed rate. The pressure loss of the whole system is appeared relatively small of 700mmAq under the normal operating condition and the temperature distribution of the incinerator internal combustion is maintained less than 1000C. Auxiliary fuel of 4.7 1/hr is required to incinerate 100kg sludge which include 87% moisture. Because the inside temperature of the incinerator is maintained less than $1000^{\circ}C$, it is predicted that the most NOx measured is produced not from the heat during the combustion process but from the oxidation of the N ingredient in the sludge. From the component analysis of ash, the organic matter is not entirely detected. Accordingly, it is estimated that the complete combustion has been accomplished in the incinerator.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.157-166
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• 2011

The virtualization layer is executed in higher authority layer than kernel layer and suitable for monitoring operating systems. However, existing virtualization monitoring systems provide simple information about the usage rate of CPU or memory. In this paper, the monitoring system using full virtualization technique is proposed, which can monitor virtual machine's dynamic kernel object as memory, register, GDT, IDT and system call table. To verify the monitoring system, the proposed system was implemented based on KVM(Kernel-based Virtual Machine) with full virtualization that is directly applied to linux kernel without any modification. The proposed system consists of KvmAccess module to access KVM's internal object and API to provide other external modules with monitoring result. In experiments, the CPU utilization for monitoring operations in the proposed monitering system is 0.35% when the system is monitored with 1-second period. The proposed monitoring system has a little performance degradation.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.4
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• pp.103-110
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• 2018

Services that enhance user convenience by using various IoT devices are increasing with the development of Internet of Things(IoT) technology. Also, since the price of IoT sensors has become cheaper, companies providing services by collecting and utilizing data from various sensors are increasing. The smart IoT home system is a representative use case that improves the user convenience by using IoT devices. To improve user convenience of Smart IoT home system, this paper proposes a method for the control of related devices based on data analysis. Internal environment measurement data collected from IoT sensors, device control data collected from device control actuators, and user judgment data are learned to predict the current home state and control devices. Especially, differently from previous approaches, it uses deep neural network to analyze the data to determine the inner state of the home and provide information for maintaining the optimal inner environment. In the experiment, we compared the results of the long-term measured data with the inferred data and analyzed the discrimination performance of the proposed method.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.731-740
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• 2001

Multi-distributed web cluster model expanding conventional cluster system is the cluster system which processes large-scaled work demanded from users with parallel computing method by building a number of system nodes on open network into a single imaginary network. Multi-distributed web cluster model on the structured characteristics exposes internal system nodes by an illegal third party and has a potential that normal job performance is impossible by the intentional prevention and attack in cooperative work among system nodes. This paper presents the mutual authentication protocol of system nodes through key division method for the authentication of system nodes concerned in the registration, requirement and cooperation of service code block of system nodes and collecting the results and then designs SNKDC which controls and divides symmetrical keys of the whole system nodes safely and effectively. SNKDC divides symmetrical keys required for performing the work of system nodes and the system nodes transmit encoded packet based on the key provided. Encryption packet given and taken between system nodes is decoded by a third party or can prevent the outflow of information through false message.