• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.289-292
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• 2001

A Novel fully-differential bipolar current-controlled current amplifier(CCCA) for electrically tunable circuit design at current-mode signal processing were designed. The CCCA was consisted of fully-differential subtracter and fully-differential current gain amplifier. The simulation result shows that the CCCA has current input impedance of 0.5 Ω and a good linearity. The CCCA has 3-dB cutoff frequency of 20 MHz for the range over bias current 100$mutextrm{A}$ to 20 ㎃. The power dissipation is 3 mW.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.836-845
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• 2001

A Novel fully-differential bipolar current subtracter(FCS) and its application to current controlled current amplifier(CCCA) for high-accuracy current-mode signal processing were designed. To obtain full-differential current output, the FCS was symmetrically composed of two current follower with low current-input impedance. The CCCA to control output current by the bias current was consisted of the subtracter and a current gain amplifier(CGA) with single-ended current output.. The simulation result shows that the FCS has current-input impedance of 5 Ω and a good linearity. The CCCA has 3-dB cutoff frequency of 20 MHz for the range over bias current 100 $\mu$A to 20 mA. The power dissipation of the FCS and CCCA are 1.8 mW and 3 mW, respectively.

• Journal of Technology Innovation
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• v.15 no.2
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• pp.83-102
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• 2007

This study extends the existing method of Technology Forecasting with Data Envelopment Analysis (TFDEA) by incorporating a ranking method into the model so that we can reduce the required number of DMUs (Decision Making Units). TFDEA estimates technological rate of change with the set of observations identified by DEA(Data Envelopment Analysis) model. It uses an excessive number of efficient DMUs(Decision Making Units), when the number of inputs and outputs is large compare to the number of observations. Hence, we investigated the possibility of incorporating CCCA(Constrained Canonical Correlation Analysis) into TFDEA so that the ranking of DMUs can be made. Using the ranks developed by CCCA(Constrained Canonical Correlation Analysis), we could limit the number of efficient DMUs that are to be used in the technology forecasting process. The proposed hybrid model could establish technology frontiers with the efficient DMUs for each generation of technology with the help of CCCA that uses the common weights. We applied our hybrid model to forecast the technological progress of main battle tank in order to demonstrate its forecasting capability with practical application. It was found that our hybrid model generated statistically more reliable forecasting results than both TFDEA and the regression model.

• Journal of the military operations research society of Korea
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• v.33 no.2
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• pp.61-73
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• 2007

We examined technological forecasting of extended TFDEA(Technological Forecasting with Data Envelopment Analysis) and thereby apply the extended method to the technological forecasting problem of main battle tank. The TFDEA has the possibility of using comparatively inefficient DMUs(Decision Making Units) because it is based on DEA(Data Envelopment Analysis), which usually leads to multiple efficient DMUs. Therefore, TFDEA may result in incorrect technological forecasting. Instead of using the simple DEA, we incorporated the concept of Super-efficiency, Cross-efficiency, and CCCA(Constrained Canonical Correlation Analysis) into the TFDEA respectively, and applied each method to the case study of main battle tank using verifiable practical data sets. The comparative analysis shows that the use of CCCA with TFDEA results in very comparable prediction accuracies with respect to MAE(Mean Absolute Error), MSE(Mean Squared Error), and RMSE(Root Mean Squared Error) than using the concept of Super-efficiency and Cross-efficiency.

• The KIPS Transactions:PartC
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• v.8C no.3
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• pp.245-252
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• 2001

인터넷의 이용증가와 전자상거래의 활성화 등으로 인해 급속도로 발전하는 공개키 기반구조에 능동적으로 대처하기 위해서는 확정성과 상호 운용성, 관리용이성, 나 공개키 기반구조 기관의 수용 등 여러 가지 문제를 고려한 인증 모델이 제시되어야 한다. 이 논문에서는 인터넷에서 이기종의 컴퓨터들이 서로 연결되어 자료를 공유하고 분산되어 실행할 수 있는 개방 분산 시스템인 CORBA 기반의 상호인증 모델을 설계한다. 공개케 기반 시스템(PKI)을 도입하되 CCCA(Cross Certification CA)를 이용하여 효율적으로 상호인증 할 수 있는 모듈과 인터페이스를 설계하고 기존 모델과 비교 분석하여 우수성을 증명한다.

• Journal of the military operations research society of Korea
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• v.32 no.1
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• pp.51-72
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• 2006

There are many occasions that the performance of a corps is influenced not only by its own efforts but by the commander of the next higher unit in a vertical organizational structure. When the direction of the commander in the next higher organization is different from that of the actual evaluation agency, the unit under evaluation may get rated lower than what it should deserve. This study suggests an alternative method to evaluate the performance of military units in the situation that there exist critical environmental factors which affect the performance. This method employes DEA, a non parametric method, and Constrained Canonical Correlation Analysis(CCCA), a parametric method which is used to estimate a efficient frontier with multiple dependent variables and constraints. This article also exploits a set of categorical environmental variables in the CCCA to improve the fairness of performance evaluation. It is shown that the introduction of the categorical variables helps evaluating the true performance of individual units such as battalions subordinated to different next higher commanders.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.262.1-262.1
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• 2003

Anti-tumor, anti-viral and anti-leukemic activity of cordycepin are well known. Adenosine was reported to induce an apoptosis in human leukemia cells. CM has been widely used as traditional medicinal herbs in China. Previously, we reported the results relating the isolation and characterization of cordycepin and adenosine from the cultured fruiting bodies of CM. We further studied the manufacturing process of CCCA for the prupose of developing anti-leukemic agents. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.140.1-140.1
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• 2003

Permanent cell culture lines derived from human cancer tissue are important experimental models in the study of human cancer cell proliferation. The in vitro effects of C. militaris and its extracted fractions on the human breast cancer (SK-BR3), liver cancer (SK-Hep1, HepG2), kidney cancer (p15), lymphoma (Jurkat) were studied. F1 (CCCA, crude cordycepin containing adenosine), F2 (ethanol precipitation), F3 (ethanol soluble supernatant) and F4 (fraction of through SK-1B) significantly stimulated in vitro cytotoxic in human cancer cell lines. (omitted)

• Natural Product Sciences
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• v.9 no.4
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• pp.291-298
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• 2003

Anti-diabetic effect of various fractions of Cordyceps militaris (CM), CCCA (crude cordycepin containing adenosine), CMESS (ethanol soluble supernatant), and cordycepin were evaluated in streptozotocin (STZ) induced diabetic mice, CMESS showed potent inhibitory activity of 34.7% in starch-loaded mice (2 g/kg) while acarbose as a positive standard exhibited 37.8% of inhibition rate. After 3 days administration (50 mg/kg), cordycepin (0.2 mg/kg), and acarbose (10 mg/kg) dramatically reduced blood glucose level (inhibition ratio: 46.9%, 48.4% and 37.5% respectively). CCCA that has high contents of cordycepin (0.656 mg/4 mg) did not influence on reducing blood glucose level. The proliferation of splenocytes and peritoneal macrophages derived from STZ-induced diabetic mice administered samples were evaluated out by addition of mitogens to see the stability of the usage of these herbal medicines. Proliferation of T-lymphocyte was significantly decreased; while NO production was increased more than two fold to STZ control in the cordycepin-administered group. Changes of serum enzyme levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were also evaluated. Cordycepin administered group was appeared to acarbose. We conclude that CMESS and cordycepin may be useful tools in the control of blood glucose level in diabetes and promising new drug as an anti-hyperglycemic agent without defects of immune responses and other side effects.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.139.2-139.2
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• 2003

The in vitro effects of extracted fractions of C. militaris on the secretion of cytokines in murine macrophage cell line, RAW 264.7 were studied. F1 (crude cordycepin containing adenosine), F2 (ethanol precipitation), F3 (ethanol soluble supernatant) and F4 (fraction of through SK-1B) significantly stimulated the production of cytokine and nitric oxide (NO) on murine macrophage cell line RAW264.7. We examined how the ethanol extract of C. militaris regulates production of interleukine 1-beta(IL-1$\beta$), tumor necrosis factor-alpha (TNF-$\alpha$), and NO in vitro. (omitted)