• 약학회지
• /
• 제60권3호
• /
• pp.135-140
• /
• 2016

Heat shock protein 90 (Hsp90) is a ubiquitous molecular chaperone, which is associated with stabilization of many oncogenic proteins for cancer cell survival. Hsp90 is overexpressed 2-10 fold higher in cancer cells than normal cells. Due to its potential to simultaneously disable multiple signaling pathway, Hsp90 has been identified as a validated target for cancer therapy. Accordingly, we designed and synthesized 2',4'-dimethoxychalcone derivatives to inhibit Hsp90 chaperone function. Among 2',4'-dimethoxychalcone derivatives, we found that compound 1g disrupted Hsp90 chaperoning function and impaired the growth of cancer cells. These findings indicated that 1g could serve a potential lead compound to target Hsp90 in cancer chemotherapy.

• 한국컴퓨터정보학회논문지
• /
• 제21권12호
• /
• pp.35-41
• /
• 2016

In this paper, we propose a new real-time dead pixel detection method based on spatial compare filtering, which are usually used in the small target detection. Actually, the soft dead and the small target are cast in the same mold. Our proposed method detect and remove the dead pixels as applying the spatial compare filtering, into the pixel outputs of a detector after the non-uniformity correction. Therefore, we proposed method can effectively detect and replace the dead pixels regardless of the non-uniformity correction performance. In infrared camera, there are usually many dead detector pixels which produce abnormal output caused by manufactural process or operational environment. There are two kind of dead pixel. one is hard dead pixel which electronically generate abnormal outputs and other is soft dead pixel which changed and generated abnormal outputs by the planning process. Infrared camera have to perform non-uniformity correction because of structural and material properties of infrared detector. The hard dead pixels whose offset values obtained by non-uniformity correction are much larger or smaller than the average can be detected easily as dead pixels. However, some dead pixels(soft dead pixel) can remain, because of the difficulty of uncleared decision whether normal pixel or abnormal pixel.

• 전자공학회논문지S
• /
• 제35S권7호
• /
• pp.86-94
• /
• 1998

The rosette-scan seeker is a device mounted on the infrared guided missile. It offers the positions and iamges of target to missiles servo system by scanning a space about target in rosette pattern with a single detector. An instantaneous field of view (IFOV), which is a diameter of a detector moving along the path of the rosette pattern, has the property that its smaller size provide the less interference of background signals and detector noise. If its size is too small to voer the total field of view (TFOV), however, it produces the invisible regions in the TFOV. In this case, the invisible regions cause the performance of the seeker to deteriorate. For full scan-coverage, it is necessary to design the small IFOV without the invisible regions in the TFOV, as possible. In this paper, we propose the new method of designing the smaller IFOV than the conventional method and verify full coverage of the scanned region. By comparing the nose equivalent flux density (NEFD) of the proposed method with the that of the conventional one, we confirm that the former is better than the latter in terms of performance.

• 통합자연과학논문집
• /
• 제5권1호
• /
• pp.32-37
• /
• 2012

Chemokine receptor antagonists have potential applications in field of drug discovery. Although the chemokine receptors are G-protein-coupled receptors, their cognate ligands are small proteins (8 to 12 kDa), and so inhibiting the ligand/receptor interaction has been challenging. The application of structure-based in-silico methods to drug discovery is still considered a major challenge, especially when the x-ray structure of the target protein is unknown. Such is the case with human CCR2 and CCR5, the most important members of the chemokine receptor family and also a potential drug target. Herein, we review the success stories of combined receptor modeling/mutagenesis approach to probe the allosteric nature of chemokine receptor binding by small molecule antagonists for CCR2 and CCR5 using Rhodopsin as template. We also urged the importance of recently available ${\beta}2$-andrenergic receptor as an alternate template to guide mutagenesis. The results demonstrate the usefulness and robustness of in-silico 3D models. These models could also be useful for the design of novel and potent CCR2 and CCR5 antagonists using structure based drug design.

• 정보보호학회논문지
• /
• 제22권3호
• /
• pp.679-689
• /
• 2012

2009년 7.7 DDoS 공격은 기존 DDoS공격과는 달리 감염 PC별로 적은 용량의 패킷 전송으로 웹페이지를 마비시켰으며, 또한 HTTP Flooding이라는 공격기법을 활용하여 공격을 성공한 사례였다. DDoS 공격은 시스템을 손상시키는 것이 아니라 일시적으로 서비스의 가용성을 해치는 것이므로, 효과적인 방어를 위해서는 공격자의 공격보다 높은 가용성을 확보하거나, 정확한 방어전략을 실행하여 서비스 시스템의 가용성을 확보하는 방법 등이 있다. 본 논문에서는 기존의 가용량 증설을 통한 방어기법과 달리, DDoS 공격의 특성에 기반하여 공격을 차단하여 서비스 시스템의 가용성을 확보하는 다단계 방어기법을 활용한 웹사이트 전용 DDoS 방어시스템 구축 방안을 제안한다.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권8호
• /
• pp.137-148
• /
• 2021

The study investigates the existence of an optimal level of cash and the firm characteristics influencing the decision to hold cash, and the adjusting speed of the cash holdings to the target level. It highlights the heterogeneity of cash adjustment speed in the Vietnam market. The research employs the 417 samples of Vietnamese non - financial listed firms in the period of 2010 to 2019. The study uses the Pool OLS model, Fixed effect model (FEM), Random effect model (REM), and GMM model. According to the research findings, there is an optimal amount of cash at which the firm's value is maximized in Vietnamese listed firms, and the majority of the firms in the sample retain cash over the target level. Furthermore, the study demonstrates that firms actively modify their cash holdings to the optimal level with an adjustment speed of less than one owing to adjustment cost constraints. This speed varies between groupings of enterprises with different characteristics, underlining the heterogeneity of the adjustment speed even more. Small deviation firms adjust more rapidly than large deviation firms. Large free cash flow (FCF) firms adjust more readily than small FCF firms, and fiscal deficit firms modify more rapidly than firms with a financial surplus.

• 한국물환경학회지
• /
• 제26권2호
• /
• pp.200-207
• /
• 2010

The sewage treatment plants to be built to improve the water quality of the Mankyung River will total 11, of which combined capacity will reach $39,850m^3/day$, and saying in detail, 5 at Gunsan city, 2 at Iksan city, 1 at Kimje city and 3 at Wanju gun, The scenario for water quality improvement was developed, considering the conditions of plant operation ratio and the accomplishment of the water quality target (BOD 4.4 mg/L, T-P 0.356 mg/L) at the end of the watershed of Mankyung B was predicted, making use of QUAL2E model. As a result of prediction using QUAL2E model based on scenarios with 70% and 100% of operation ratio, respectively, at 11 plants in 2010, the water quality at the watershed of Mankyung B was estimated at 4.322 mg/L which was lower than the target of BOD 4.4 mg/L, indicating the target water quality was achieved, when it comes to 70% of operation ratio, But in case of T-P, it was estimated at 0.565 mg/L, which was higher than the target. When it comes to 100% of operation ratio, T-P also was 0.563 mg/L which exceeded the target, 0.356 mg/L. As indicated above, the effect of water quality improvement appeared very insignificant, which was attributable to the limit of small scale sewage treatment plant in total reduction capacity. Hence, the measures for additional reduction in a bid to achieve the target water quality of T-P at the designated location need to be taken, and the measures to build the Sewage treatment facilities at the place where the pollution is significantly caused by T-P appeared to be required as well.

• ETRI Journal
• /
• 제40권2호
• /
• pp.188-196
• /
• 2018

This paper presents a pulse radar system to detect drones based on a target fluctuation model, specifically the Swerling target model. Because drones are small atypical objects and are mainly composed of non-conducting materials, their radar cross-section value is low and fluctuating. Therefore, determining the target fluctuation model and applying a proper integration method are important. The proposed system is herein experimentally verified and the results are discussed. A prototype design of the pulse radar system is based on radar equations. It adopts three different pulse modes and a coherent pulse integration to ensure a high signal-to-noise ratio. Outdoor measurements are performed with a prototype radar system to detect Doppler frequencies from both the drone frame and blades. The results indicate that the drone frame and blades are detected within an instrumental maximum range. Additionally, the results show that the drone's frame and blades are close to the Swerling 3 and 4 target models, respectively. By the analysis of the Swerling target models, proper integration methods for detecting drones are verified and can thus contribute to increasing in detectability.

• 한국의학물리학회지:의학물리
• /
• 제3권1호
• /
• pp.53-62
• /
• 1992

최근 두개부 종양의 방사성물질의 자입과 방사선입체조사에 의한 뇌수술이 개발되어 의료계 에 많은 관심을 끌고 있다. 또한 방사선수술등은 비관혈적인 체외조사이므로 뇌정위수술용 좌표계의 전산화단층촬영을 이용한 표적중심결정이 매우 중요하다. 현재 알려진 방법은 뇌정위수술용좌표계의 전산화단층찰영에 대한 직교성하에서 비교적 정확하게 표적의 위치를 결정하게 되나, 임상현장에서 직교성유지는 실제 어려운 실정이다. 이에 필자들은 임의의 비직교성 스켄하에서 정확한 표적좌표를 얻기위한 알고리즘을 사용하였으며, 표적오차는 평균 0.02$\pm$0.3mm를 보였다.

• 한국자기학회지
• /
• 제23권5호
• /
• pp.159-165
• /
• 2013

능동형 자기센서는 근거리에서 정확한 표적 탐지가 가능하지만 대상 표적 관점에서는 이러한 센서의 위협을 극복할 수 있는 마땅한 대항책이 없기 때문에 세계 각국의 수중유도무기에서 기폭신관용 센서로 널리 사용하고 있다. 하지만 근래에는 표적의 명중률 향상을 위한 목적으로 능동형 자기센서의 표적 탐지거리를 증대시키는 것에 대한 요구가 끊임없이 제기되고 있다. 표적 탐지거리를 증대시키는 방법 중의 하나는 송신기의 코어 형상 최적화를 통한 송신 코어의 자기소거인자를 최소화하고, 이를 통해서 송신기 출력을 향상시키는 것이다. 따라서 본 논문에서는 수중유도무기에 적용되는 능동형 자기센서의 송신출력 향상을 위한 송신기 코어 형상 설계와 관련하여 유한요소해석 및 실세 제작된 송신기를 대상으로 비교 시험을 수행하였고, 그 결과 송신기 코어의 형상은 송신 출력 향상에 매우 중요한 인자임을 확인하였다.