• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.262-268
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• 2010

In this paper, a high power active tunable bandpass filter made of dielectric resonators and varactor diodes is designed using the active capacitance circuit generating negative resistance for tuning cellular TX, RX band. An active capacitance circuit's series feedback circuit using GaAs HFET whose $P_{1dB}$ is 32 dBm is used for compensating the losses from the varactor diodes of the tunable bandpass filter. The tuning elements, the varactor diodes are used as the back-to-back configuration to achieve the high power performance, The designed active capacitance circuit improves the insertion loss characteristics. The designed 2-stage active tunable dielectric bandpass filter at cellular band can cover from 800 MHz to 900 MHz. The insertion losses at 836 MHz and 881.5 MHz with 25 MHz bandwidth are 0.48 dB and 0.39 dB, respectively. The $P_{1dB}$ of the designed bandpass filter at TX and RX band are measured as 19.5 dBm and 23 dBm, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.703-717
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• 2002

This paper illustrates the implementation of a scalable shared buffer asynchronous transfer mode (ATM) switch. The designed shared buffer ATM switch has a shared buffet of a pipelined memory which has the access time of 4 ns. The high-speed buffer access time supports a possibility of the implementation of a shared buffer ATM switch which has a large switching capacity. The designed switch architecture provides flexible switching performance and port size scalability with the independence of queue address control from buffer memory control. The switch size and the buffer size of the designed ATM switch can be reconfigured without serious circuit redesign. The designed prototype chip has a shared buffer of 128-cell and 4 ${\times}$ 4 switch size. It is integrated in 0.6um, double-metal, and single-poly CMOS technology. It has 80MHz operating frequency and supports 640Mbps per port.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.621-628
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• 2008

Many of today's businesses need IT system's flexibility for on-demand business which can be rapidly adapted to environment changes. Service oriented architecture (SOA) provides the infrastructure which makes business flexibility possible under the on-demand operating environment. Therefore, to satisfy these requirements, new approach for assuring business flexibility and enhancing reuse is needed. In this paper, we propose an approach for developing a business process family model (BPFM) in which the variabilities in business process family can be explicitly represented by using the variability analysis method of software product line. In addition, we describe the supporting tool for this approach. It can model the BPFM and generate automatically BPMs through decision and pruning process from BPFM. By using our approach, the business and its IT system can correspond to business environment changes rapidly and efficiently.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.747-754
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• 2009

Software product line engineering is an approach to creating core assets by systematically exploits common that can be highly reusableand different characteristics in related system families that is domain. By adapting this approachin object and component paradigm, software productivity is extended. Recently, Software development paradigm is changed to service oriented paradigm which is using services that are core assets. Therefore, to develop service oriented software more flexible, systematic and to enhance business agility about business changes, we need adaptation of product line to creation of services that are core assets. In this paper, we propose an approach to create and specify domain service through combine of product line and service oriented paradigm. Domain service explicitly specifies commonality and variability by domain service common/optional property variability, operation type variability, message type variability. By using this approach, it can support efficient and flexible service oriented development by producing various services through customization of domain service for the purpose.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4583-4591
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• 2010

Existing XML-based variable data publishing, in which a user has to manually prepare and edit template rules, is rather difficult for general users to create documents. Especially when processing large variable XML documents such as manuals or technical documents, fast document formatting is required to provide fast response speed for editing, which the existing batch processing cannot provide. This paper proposes a variable data publishing system with dynamic editing and formatting function, which support fast formatting upon user's request for large volume documents as well as for template editing through interaction by displaying the result of template-based variable documents on WYSIWYG screen. Proposed system can be effectively used for creating customized documents with many variable data that can be changed according to individual characteristics such as individual, company or area; source documents, template documents and formatted documents adopt XML, XSLT and XPath standards suggested by W3C, which facilitates extension to web document processing system.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.373-380
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• 2014

With a view to the commercialization of the Korean automatic variable-gauge bogie in the Eurasia railway system, the aim of this research was to perform an economic analysis concerning the possible introduction and operation of this bogie at the present time. For this purpose, we compared the possible types of freight connection service for container transportation, transshipment and the gauge-adjustable system, estimating the total life-cycle cost (LCC) incurred by each system, depending on type and quantity, over the whole process of acquisition, operation, maintenance and disposal. Based on this, we presented a case-by case analysis. Furthermore, in estimating economic feasibility, we analyzed the cost-benefit ratio taking into account not only the objective LCC, but also the reduced time required for the gauge-change and customer convenience. After estimating the LCC and analyzing the cost-benefit ratio of the respective systems, we demonstrated the economic superiority of view of the gauge adjustable system.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.321-326
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• 2003

We constructed grating- tuned external cavity semiconductor lasers using Littman and Littrow configuration, for which the wavelengths are tuned by rotation of the grating. This wavelength tunable semiconductor laser is one of the main devices of WDM optical communication. In Littman configuration, the wavelength range of about 60 nm (The C- and L-band range of 1,530~1,590 nm) was obtained by changing the incidence angle of the grating about $\pm$1$^{\circ}$ from the incidence angle of 70$^{\circ}$. In the 40 nm tuning range, the output power variation was less than 1.25 ㏈ and the side mode suppression ratio(SMSR) was 32 ㏈. In Littrow configuration (The incidence angle and the first order diffraction angle is the same, i.e. $\alpha$=$\delta$), the wavelength tuning range was about 80 nm for the same conditions used in Littman configuration except the incidence angle ($\alpha$=49$^{\circ}$). In 60 nm tuning range, the output power variation was less than 1.5 ㏈ and SMSR was 35 ㏈.

• Journal of Software Engineering Society
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• v.24 no.3
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• pp.77-89
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• 2011

Software product line engineering is a software reuse paradigm that helps organizations improve software productivity and quality by developing software products from reusable core assets. For the satisfaction of common and variable requirements among products in the product line, the core assets must be configurable according to the selection of variable features. Therefore, unlike software architecture model of a single product, product line architecture model must embed and express variabilities among the products. Many researches have proposed methods of embedding and expressing variabilities in the product line architecture models, but there are few comparative studies on the proposed methods. In this paper we discuss strong points and weak points of the proposed methods and compare expressiveness of the methods, which helps select a proper method.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.259-267
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• 2019

As the change in social awareness regarding cats is consistent with the lifestyle of modern people who seek an independent life, the number of cats owned as a pet and its market will continue to increase. The compainion animals are not just pets to pet owners, but people communicate with their pets and the pets have begun to be recognized as a member of their family. Although the pet industry has been steadily growing and the number of cats owned by households is rapidly increasing, there is a lack of study on products based on understanding the characteristics and behavior of cats. The purpose of this study is to propose a versatile furniture design considering the behavior characteristics of cats. The versatile furniture that is easy to move and rearrange according to necessity and the environment of residential space always pays to make better use of the space. We would like to propose versatile furniture that can satisfy the aesthetic pleasures of cats and can be used as furniture at the same time depending on purpose and situation. This study aims to develop the design of furniture that can make a better environment for pets and pet owners, an it is expected to be a basic study of furniture design for them.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.483-488
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• 2020

In recent years, the demand for wireless devices incorporating several wireless communication systems into one has been increasing in order to provide services that meet the diverse needs of consumers. Wireless devices consisting of various wireless communication systems require many frequency fixed filters. A frequency tunable filter can replace a number of frequency fixed filters in the wireless devices. If a frequency tunable filter is used in wireless systems, the system can be configured more efficiently. In this paper, a 3-pole frequency tunable BPF(bandpass filter) operating in the frequency band of 800 ~ 2400MHz is designed. In order to widen the operating frequency band, a tuning screw is designed to have a step and a linear motor is used to facilitate the adjustment of the tuning screw. The implemented frequency tunable BPF operates in the designed frequency range and has the maximum insertion loss of 2.82dB in the channel band and the minimum attenuation of 18.7dB at ± 50MHz frequency offset from the center frequency of the band.