• Journal of Communications and Networks
• /
• v.12 no.1
• /
• pp.19-29
• /
• 2010

Recently, spectrum sensing has been intensively studied as a key technology in realizing the cognitive radio. There have been advances in the performance of spectrum sensing through both multi-antenna and cooperative sensing schemes. In this paper, the performances and complicated scenarios of the latest spectrum sensing schemes are analytically compared and arranged into a technical tree while considering practical concerns. This paper will give a macroscopic view of spectrum sensing and will also provide insight into future spectrum sensing works.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.10
• /
• pp.441-446
• /
• 2003

The chemical mechanical polishing (CMP) process is now widely employed in the ultra large scale integrated (ULSI) semiconductor fabrication. Especially, shallow trench isolation (STI) has become a key isolation scheme for sub-0.13/0.10${\mu}{\textrm}{m}$ CMOS technology. The most important issues of STI-CMP is to decrease the various defects such as nitride residue, dishing, and tom oxide. To solve these problems, in this paper, we studied the planarization characteristics using slurry additive with the high selectivity between $SiO_2$ and $Si_3$$N_4$ films for the purpose of process simplification and in-situ end point detection. As our experimental results, it was possible to achieve a global planarization and STI-CMP process could be dramatically simplified. Also, we estimated the reliability through the repeated tests with the optimized process conditions in order to identify the reproducibility of STI-CMP process.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.6
• /
• pp.521-525
• /
• 2014

Circulating tumor cells (CTCs) in the bloodstream of cancer patients provide an accessible source for detection, characterization, and monitoring of nonhematological cancers. The effectiveness of the CTC-Chip for the isolation of ovarian cancer cells was demonstrated by adapting the herringbone-chip (HB-Chip). The motions of the particles on the HB chip were simulated by a unique combination of buoyant, gravitational forces, and helical flows with a computational modeling. The motions of cells are demonstrated by applying polystylene bead and ovarian cancer cells into the microfabricated HB-Chip. The experimental results from beads and cells are well accordance with the simulated ones, as previously reported by Toner group. Thus, I expect that these modeling and experimental skills will play key roles in the clinical applications on CTC isolation as well as the basic research on characterization of CTCs under flow.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.05a
• /
• pp.68-69
• /
• 2009

Heat Assisted Magnetic Recording (HAMR) is one of the most promising candidates for high density magnetic storages over 1 Tb/$in^2$ areal density. Since the precise light delivery to the head is a key factor to realize HAMR application, it is required to establish the light delivery using micro laser module and micro actuator. For the careful control of micro actuator, a laser module was designed including laser diode, optical fiber, collimating lens, and fabricated V-groove substrate. In addition, the basic aligning method between the laser module and HAMR head was studied by the detection of current change in photo diode due to the amount of reflected light from the head.

• Journal of Korea Society of Industrial Information Systems
• /
• v.11 no.3
• /
• pp.40-46
• /
• 2006

Automatic recognition of container identifier is one of key factor to implement port automation and increase distribution throughput. In this paper, I propose a method of container identifier recognition on various input images using color based edge detection and character verification algorithm, I tested the proposed method on 350 container images and it showed good results.

• Journal of Information Processing Systems
• /
• v.15 no.6
• /
• pp.1265-1276
• /
• 2019

Data deduplication is a common method to improve cloud storage efficiency and save network communication bandwidth, but it also brings a series of problems such as privacy disclosure and dictionary attacks. This paper proposes a secure deduplication scheme for cloud storage based on Bloom filter, and dynamically extends the standard Bloom filter. A public dynamic Bloom filter array (PDBFA) is constructed, which improves the efficiency of ownership proof, realizes the fast detection of duplicate data blocks and reduces the false positive rate of the system. In addition, in the process of file encryption and upload, the convergent key is encrypted twice, which can effectively prevent violent dictionary attacks. The experimental results show that the PDBFA scheme has the characteristics of low computational overhead and low false positive rate.

• Preventive Nutrition and Food Science
• /
• v.5 no.1
• /
• pp.7-9
• /
• 2000

Variouss concentrationss of free malonaldehyde were prepared from 1,1,3,3-tetraethoxy propane (TEP). Spectrophoto-metric determination and HPLC analysis of free malonaldehyde instead of malonaldehyde-thiobaribituric acid (MA-TBA) complex were conducted. Malonaldehyde was well separated on a $\mu$Bondapak C18 column. The absorbances at 254 nm and the HPLC peak areas of free malonaldehyde increased with the increase in its concentration. The correlation coefficient between absorbances and peak areas was 0.998. The total time elapsed to conduct the whole procedure was less than 15 minutes. This method directly measured the amount of free malonaldehyde in a short period of time successfully. This procedure is expected to be used as a rapid, accurate and specific means to de-termine the development of lipid oxidation in food.

• Journal of the Korean Society for Railway
• /
• v.8 no.1
• /
• pp.1-5
• /
• 2005

This paper has presented the parallel cyclic redundancy check (CRC) technique that performs CRC computation in parallel superior to the conventional CRC technique that processes data bits serially. Also, it has showed that the implemented parallel CRC circuit has been successfully applied to the inductively coupled passive RFTD system working at a frequency of 13.56㎒ in order to process the detection of logical faults more fast and the system has been verified experimentally. In comparison with previous works, the proposed RFID system using the parallel CRC technique has been shown to reduce the latency and increase the data processing rates about 15％ In the results. Therefore, it seems reasonable to conclude that the parallel CRC realization in the RFID system offers a means of maintaining the integrity of data in the high speed RFID system.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.1235-1240
• /
• 2004

This paper has presented the parallel cyclic redundancy check (CRC) technique that performs CRC computation in parallel superior to the conventional CRC technique that processes data bits serially. Also, it has showed that the implemented parallel CRC circuit had been successfully applied to the inductively coupled passive RFID system working at a frequency of 13.56MHz in order to process the detection of logical faults more fast and the system had been verified experimentally. In comparison with previous works, the proposed RFID system using the parallel CRC technique has been shown to reduce the latency and increase the data processing rates in the results. Therefore, it seems reasonable to conclude that the parallel CRC realization in the RFID system offers a means of maintaining the integrity of data in the high speed RFID system.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 1995.11a
• /
• pp.115-125
• /
• 1995

본 논문에서는 컴퓨터 시스템에서 침입 감지 시스템을 설계함에 있어서 사용될 수 있는 새로운 방법인 Event Sequence Tracking 방법을 제안하였다. Event Sequence Tracking 방법에서는 컴퓨터 시스템의 공격방법을 크게 두가지로 분류한다. 첫번째는 일련의 시스템 명령어를 이용한 공격방법이고 두번째는 침입자 자신이 만들었거나 다른 사람으로부터 얻은 프로그램을 이용하는 방법이다. 첫번째 공격방법에 대한 감지방법은 시스템을 공격할 때 사용한 일련의 시스템 명령어들을 감사 데이타를 분석하여 찾아내고 이 결과를 기존에 알려진 공격 시나리오들과 비교하여 침입자를 찾아내는 방식이다. 두번째 공격방법에 대한 감지 방법은 보안 관리자가 정해놓은, 시스템에서 일반 사용자가 할 수 없는 행위에 관한 보안 정책에 따라 Key-Event 데이타 베이스를 만들고 여기에 해당하는 event의 집합을 감사 데이타에서 찾아내는 방법이다. Event Sequence Tracking 방법은 Rule-based Penetration Identification 방법의 일종으로서 시스템의 공격방법을 분류하여 컴퓨터 시스템에의 침입을 효과적으로 감지할 수 있다는 것과 rule-base의 생성과 갱신을 함에 있어서 보다 간단하게 할 수 있다는 장점을 갖는다.