• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.429-436
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• 2005

The linear modulation method which has high spectrum efficiency when applying in mobile communication system, the problem occurs. In order to solve like this problem non-linearity characteristic of the power amplifier linearity against the method which it does it investigated. It used a design objection and it implemented the microwave power amplifier. The amplifier which it produces used the micro-strip line and when it imput power 13 dBm from center frequency, the possibility of getting the output power of 28 dBm.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1579-1581
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• 2011

페이스북(Facebook)과 트위터(Twitter)등으로 각광 받는 소셜 네트워크 서비스(Social Network Service)는 사용자의 온라인과 오프라인에 구축된 인맥 네트워크를 기반으로 한다. SNS내의 소셜커머스, 소셜어플리케이션 등의 다양한 기능이 추가 되면서 새로운 온라인 서비스 시장이 등장하게 되었다. 초기의 새로운 가상 인맥 늘리기 수단으로 사용되었던 SNS서비스는 스마트폰의 등장과 카메라, 마이크 등의 추가 디바이스와 서비스간의 연계가 가능해 지면서 이용자들의 새로운 정보 생성과 실시간 커뮤니케이션이 가능해 졌다. 또한 SNS를 통한 정보의 흐름은 텍스트 기반의 한방향 정보 전달 틀에서 소리와 이미지, 동영상등의 다양한 미디어가 취합되는 공간이 됨으로서 사용자와 다른 사용자간의 상호 작용이 가능한 쌍방향 소통으로 현실의 정보를 보다 정확하고 빠르게 전달할 수 있는 하나의 미디어 형태로 진화하는 중이다. 본 논문에서는 소셜 서비스에서 생성된 정보가 집단 협업(Mass Collaboration)을 이룰 때 갖는 신뢰성을 기대하여 키워드 중심의 정보 형성에 따른 SNS 활용 방법을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.552-555
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• 2020

최근 코로나 관련 온라인 강의가 늘어남에 따라 적은 도구를 이용한 온라인과 오프라인 강의의 장점은 부각, 단점은 보완한 새로운 LMS가 필요함. 웹캠과 마이크를 이용하여 수강자의 수강태도를 파악 후, 수강자의 수업태도를 향상시키는 시스템임.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.47-63
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• 2015

As knowledge is paid attention as a new production factor that generates added value, studies continue to apply knowledge management to business environment. In addition, as ICT (Information Communication Technology) was engrafted in business environment, it leads to increasing task efficiency and productivity of individual workers. Accordingly, the way that a business achieves its goal has changed to one in which its individual members are willing to take part in the organization and share information to create new values (Han, 2003) and studies for the system and service to support such transition are carrying out. Of late, a new concept called 'Enterprise 2.0' newly appears. It is the extension of Wen 2.0 and its technology, which focus on participation, sharing and openness, to the work environment of a business (Jung, 2013). Enterprise 2.0 is being used as a collaborative tool to prop up individual creativity and group brain power by combining Web 2.0 technologies such as blog, Wiki, RSS and tag with business software (McAfee, 2006). As Tweeter gets popular, Enterprise Microblog (EMB), which is an example of Enterprise 2.0 for business, has been developed as equivalent to Tweeter in business circle and SaaS (Software as a Service) such as Yammer was introduced The studies of EMB mainly focus on demonstrating its usability in terms of intra-firm communication and knowledge management. However existing studies lean too much towards large-sized companies and certain departments, rather than a company as a whole. Therefore, few studies have been conducted on small and medium-sized companies that have difficulty preparing separate resources and supplying exclusive workforce to introduce knowledge management. In this respect, the present study placed its analytic focus on small-sized companies actually equipped with EMB to know how they use it. And, based on the findings, this study examined their knowledge management strategies for EMB from the point of codification and personalization. Hypothesis -"as a company grows, it shifts EMB strategy from codification to personalization'- was established on the basis of reviewing precedent studies and literature. To demonstrate the hypothesis, this study analyzed the usage of EMB by small companies that have used it from foundation. For case study, the duration of the use was divided into 2 spans and longitudinal analysis was employed to examine the contents of the blogs. Using the key findings of the analysis, this study is aimed to propose practical implications for the operation of knowledge management of small-sized company and the suitable application of knowledge management system for operation Knowledge Management Strategy can be classified by codification strategy and personalization strategy (Hansen et. al., 1999), and how to manage the two strategies were always studied. Also, current studies regarding the knowledge management strategy were targeted mostly for major companies, resulting in lack of studies in how it can be applied on SMEs. This research, with the knowledge management strategy suited for SMEs, sets an Enterprise Microblog (EMB), and with the EMB applied on SMEs' Knowledge Management Strategy, it is reviewed on the perspective of SMEs' Codification and Personalization Strategies. Through the advanced research regarding Knowledge Management Strategy and EMB, the hypothesis is set that "Depending on the development of the company, the main application of EMB alters from Codification Strategy to Personalization Strategy". To check the hypothesis, SME that have used the EMB called 'Yammer' was analyzed from the date of their foundation until today. The case study has implemented longitudinal analysis which divides the period when the EMBs were used into three stages and analyzes the contents. As the result of the study, this suggests a substantial implication regarding the application of Knowledge Management Strategy and its Knowledge Management System that is suitable for SME.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.479-488
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• 2001

As the SoC designs complexity constantly increases, the simulation that uses their software models simply takes too much time. To solve this problem, FPGA-based logic emulators have been developed and commonly used in the industry. However, FPGA-based logic emulators are facing with the problems of which not only very low FPGA resource usage rate due to the very limited number of pins in FPGAs, but also the emulation speed getting slow drastically as the complexity of designs increases. In this paper, we proposed a new innovative emulation architecture and its software that has high FPGA resource usage rate and makes the emulation extremely fast. The proposed emulation system has merits to overcome the FPGA pin limitation by pipelined ring which transfers multiple logic signal through a single physical pin, and it also makes possible to use a high speed system clock through the intelligent ring topology. In this topology, not only all signal transfer channels among EPGAs are totally separated from user logic so that a high speed system clock can be used, but also the depth of combinational paths is kept swallow as much as possible. Both of these are contributed to achieve high speed emulation. For pipelined singnals transfer among FPGAs we adopt a few heuristic scheduling having low computation complexity. Experimental result with a 12 bit microcontroller has shown that high speed emulation possible even with these simple heuristic scheduling algorithms.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.178-192
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• 2006

The buffer overflow attack is the single most dominant and lethal form of security exploits as evidenced by recent worm outbreaks such as Code Red and SQL Stammer. In this paper, we propose microarchitectural techniques that can detect and recover from such malicious code attacks. The idea is that the buffer overflow attacks usually exhibit abnormal behaviors in the system. This kind of unusual signs can be easily detected by checking the safety of memory references at runtime, avoiding the potential data or control corruptions made by such attacks. Both the hardware cost and the performance penalty of enforcing the safety guards are negligible. In addition, we propose a more aggressive technique called corruption recovery buffer (CRB), which can further increase the level of security. Combined with the safety guards, the CRB can be used to save suspicious writes made by an attack and can restore the original architecture state before the attack. By performing detailed execution-driven simulations on the programs selected from SPEC CPU2000 benchmark, we evaluate the effectiveness of the proposed microarchitectural techniques. Experimental data shows that enforcing a single safety guard can reduce the number of system failures substantially by protecting the stack against return address corruptions made by the attacks. Furthermore, a small 1KB CRB can nullify additional data corruptions made by stack smashing attacks with only less than 2% performance penalty.

• Journal of KIISE
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• v.41 no.11
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• pp.871-877
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• 2014

Cache replacement algorithms have been developed in order to reduce miss counts. In modern processors, the performance gap between the processor and main memory has been increasing, creating a more important role for cache replacement policies. The Least Recently Used (LRU) policy is one of the most common policies used in modern processors. However, recent research has shown that the performance gap between the LRU and the theoretical optimal replacement algorithm (OPT) is large. Although LRU replacement has been proven to be adequate over and over again, the OPT/LRU performance gap is continuously widening as the cache associativity becomes large. In this study, we observed that there is a potential chance to improve cache performance based on existing LRU mechanisms. We propose a method that enhances the performance of the LRU replacement algorithm based on the access proportion among the lines in a cache set during a period of two successive replacement actions that make the final replacement action. Our experimental results reveals that the proposed method reduced the average miss rate of the baseline 512KB L2 cache by 15 percent when compared to conventional LRU. In addition, the performance of the processor that applied our proposed cache replacement policy improved by 4.7 percent over LRU, on average.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1435-1444
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• 2008

In this paper, we designed a reduced height waveguide(WG) to microstrip mode converter with a short transition length. The mode converter is composed of a mode converter using E-plane probe and a modified impedance transformer. The mode converter was designed using a probe shorted to top of a 50 ohm ridge WG. The modified impedance transformer was designed to connect the mode converter to the reduced height WG. For wide bandwidth operation, the coupling of the two parts was tuned. The structure of the mode converter was optimized for low loss and wide bandwidth, and the optimized mode converter was fabricated. The performance of the mode converter was extracted using the thru and line S-parameters for back-to-back connections, and the connector loss was calibrated. The mode converter has a right angle structure and short transition length, 7.2 mm. The mode converter shows excellent performances; the insertion loss of 0.12 dB at 15 GHz, and the return loss above 10 dB for the full Ku-band.

• KSBB Journal
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• v.24 no.2
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• pp.207-211
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• 2009

In this study, the sensing membranes for detection of pH and dissolved oxygen(DO) were prepared by immobilizing 6-aminofluorescein or ruthenium complex onto the sol-gel matrixes of GPTMS, MTMS, and TEOS and then recoated with the mixture of hydrophobic sol-gel and graphite for light insulation. The pH and DO sensing membranes recoated with the light insulation layer showed a higher sensitivity than those without light insulation layer. The sensing membranes were immobilized on the wells of 24-well microplate and used to monitor the fluorescence intensity for pH and DO in E.coli JM109 and P.pastoris X-33 fermentation processes. The change of the fluorescence intensity in the DO sensing membrane agreed with the growth patterns of microorganisms, that the membranes are valuable to monitor the DO in fermentation processes. In the case of pH monitoring, the fluorescence intensity has showed good correlation to the off-line pH data, that the pH membranes are valuable to monitor pH values in fermentations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.366-372
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• 2005

This paper presents analysis of a slot array antenna having a low side lobe level and high front-to-back ratio for a repeater system of a satellite DMB(Digital Multimedia Broadcasting) service. Antennas for this repeater system require a high gain and enough isolation to reduce interferences between signals in system. Therefore, it is necessary to suppress a side lobe level and to increase front-to-back ratio. Unlike a structure 134 by lossy microstrip lines, in this work a single cavity-backed slot antenna array using a single waveguide feed is proposed to obtain the reliability for high power handling and high radiation efficiency. The side lobe level and front-to-back ratio are enhanced with tapered array technique and an optimized vertical reflector. The measured side lobe levels in H- and E-plane are under $-33.24\;\cal{dB}$ and $-35.78\;\cal{dB}$, respectively. The front-to-back ratio over $37.84\;\cal{dB}$, and the peak gain of over $17\;\cal{dBi}$ are measured.