• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.659-667
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• 2006

In order to standardize the manufacturing processes of Hahyangju, a traditional Korean liquor, 29 yeast strains were isolated from traditional Nuruk. Strain N8 exhibited a particularly strong resistance to sugar. Strains HA2, HA3 and HA4 grew successfully in medium containing 10% ethanol. In comparison with the growth exhibited by these strains when grown in a yeast malt extract medium, the ethanol production rates for the three strains were 10.8%, 10.45%, and 10%, respectively in a yeast malt extract medium containing 25% glucose. Based on these results, HA3 was the strain selected for use in the manufacturing processes of Hahyangju and it was identified as a Saccharomyces cerevisiae strain with 97% ITS sequence similarity. The use of Saccharomyces cerevisiae HA3 causcd a decrease in the lactic acid content, acidity and growth of lactic acid bacteria in the fermentation mash. Following thc addition of Saccharomyces cerevisiae HA3 to the manufacturing process of Hahyangju, the second fermentation mash showed a 22% increase in the alcohol production rate associated with traditional fermentation; however, the amino acidity, pH and reducing sugar content showed little change. Sensory evaluation of Hahyangju fermented with S. cerevisiae HA3 also showed better scores than Hahyangju mashed by the traditional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.501-509
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• 2011

Software defined radio(SDR) has a goal that places the analog-to-digital converter(ADC) as near the antenna as possible. But current technique actually can't do analog-to-digital converting about RF band signals. So one method is studying that samples RF band signals to IF band. One of the ways Sub-Sampling technique can convert signals from RF band to IF band without oscillator. If Sub-Sampling technique is used, over 2 bands can convert signals from RF band to IF band. But due to the filter performance in RF band, it is possible to generate interference between signals that is converted in low frequency band. The effect degrades performance. In this paper, we propose one method that uses time division multiplexing(TDM) method as a solution to avoid interference between signals. By doing TDM and Sub-Sampling at the same time that method can get signals without large changes of structures.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.331-335
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• 2007

방송과 초고속인터넷 서비스를 동시에 제공할 수 있는 HFC(Hybrid Fiber Coaxial) 망은 상/하향이 비대칭 구조이며, 하향속도에 비해 상향속도가 1/10 수준이어서 상향 트래픽이 과다하게 생성될 경우 인터넷속도 지연이 발생한다. 지연에 민감한 VoIP 서비스의 품질보장 방안으로는, DOCSIS(Data Over Cable System Interface Specification) 1.1 기반의 상향 스케쥴링 기능을 이 용한 VoCM(Voice Over Cable Modem)이 있다. 그러나 별도의 VoCM을 사용해야 하며 아날로그 전화기를 사용해 IP 기반의 VoIP 단말을 사용할 수 없다는 단점이 있다. 일반 CM(Cable Modem)에 DOCSIS 1.1 Config File을 이용하여 VoIP 품질을 보장할 경우 별도의 트래픽 대역을 항상 점유해야 하는 단점이 있다. 이에, 본 논문에서는 효율적 대역폭 이용과 단말장비에 종속적이지 않은 방안을 제안하고 일반 CM을 통한 유무선 환경하에서 Dynamic QoS(Quality Of Service)를 제공할 수 있는 PCMM(Packet Cable MultiMedia) 적용 방안 및 시험결과에 대해 고찰하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.126-127
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• 2011

최근 다중 사용자 전송 기술에 관한 연구는 단일 사용자 MIMO 시스템에서의 선형적 용량증가가 다중 사용자 MIMO시스템에도 적용 될 수 있다는 것을 보여 주었다. 본 논문에서는 다중사용자 하향 채널에서 Vector Perturbation을 통해 성능 향상을 이끌어 내는 기법을 제안한다. 우리는 동시에 최대 다수의 사용자의 연결을 어느 정도 포기함으로써 서비스의 질(QoS)을 향상시키는데 중점을 두었다. 이렇게 희생한 사용자의 정보와 Perturbation 벡터를 적절히 이용하여 비트당에러율(BER)에서 큰 이득을 얻을 수 있었다. 모의 실험을 통해 Standard Vector Perturbation을 이용한 제안된 방법이 상당한 성능상 이득을 가져오는 것을 확인 할 수 있다.

• 전기의세계
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• v.22 no.2
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• pp.75-86
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• 1973

본 연구에서는 전기온돌의 안방열손실을 감소시키고 축열효과를 향상시키기 위한 방법을 검토하였으며 전기온돌에서 발생하는 진동소음을 감살시킬 수 있는 대책을 제시하였다. 저육들은 6.6[m$^{2}$] 크기의 전기온돌 model을 이용하여 건물의 구조차이와 하향열단열층의 설치유무에 따른 보온특성의 차이를 기록분석하였으며 그 결과 열전도계수가 0.03[kcal/m.hr.deg. C]정도인 내열성 Styropol과 지석 Mortar로 구성된 하향열단열층을 전기온돌의 마닥에 설치할 경우 난방부하의 감소로 인하여 축열효율이 약 2배나 향상된다는 결론을 얻었다. 또한 전기온돌공사시에 발열선을 지지할 수 있는 대각선형 Spacer를 설치하고 발열선이 매설콘크리트가 완전히 양생된 이후에 전력을 인가하면 흔히 전기온돌에서 발생하는 120-960[Hz]의 가청진동소음을 방지할 수 있다는 사실을 실험적으로 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.1040-1041
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• 2007

본 논문은 차세대 위성 개발을 위한 선행 연구의 일환으로, 다양한 플랫폼에 적용할 수 있는 위성 전자 전산 시스템 개발 검증 장비의 구성 요소인 상/하향 명령 처리 장치를 PC 에서 구동할 수 있도록 개발한 것이다. 이 PC 기반의 상/하향명령처리 시험환경은 위성의 Flight Software 로직의 검증용으로도 활용될 수 있다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.29-34
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• 2014

We introduce a number of antenna optimization problem for the zero-forcing beamforming (ZFBF) scheme to enhance energy-efficiency (EE) of the multiple-input-multiple-output broadcast channel. For proposed optimization problem, we assume an instantaneous channel gain of the ZFBF scheme as an average channel gain, given by $N_a-K+1$, in order to reduce a computational complexity of finding the number of active antennas $N_a$. Then, we convert a fractional-form objective function into a subtractive-form, and find a solution of $N_a$ and the maximum EE by an iterative process. Simulation results show that the maximum EE value obtained by proposed algorithm is almost identical to the optimal EE value by the exhaustive search method.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.3-9
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• 2015

Under the maximum transmit power constraint and the minimum rate constraint, we propose the optimal number of transmit antennas and transmit power which maximize energy-efficiency (EE) in multi-user multiple-input multiple-output (MIMO) downlink system with the maximal ratio transmission (MRT) precoding. Because the optimization problem for the instantaneous channel is difficult to solve, we use independence of individual channel, average channel gain and path loss to approximate the objective function. Since the approximated EE optimization problem is two-dimensional search problem, we find the optimal number of transmit antennas and transmit power using Lagrange multipliers and our proposed algorithm. Simulation results show that the number of transmit antennas and power obtained by proposed algorithm are almost identical to the value by the exhaustive search.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.213-221
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• 2008

Purpose: The objective of this retrospective study was to identify predictive factors for the complete pathologic response and tumor downstaging after preoperative concurrent chemoradiotherapy for locally advanced rectal cancer. Materials and Methods: Between the years 2000 and 2008, 39 patients with newly diagnosed rectal cancer without prior evidence of distant metastasis received preoperative concurrent chemoradiotherapy followed by surgery. The median radiation dose was 50.4 Gy (range, $45{\sim}59.4\;Gy$)). Thirty-eight patients received concurrent infusional 5-fluorouracil and leucovorin, while one patient received oral capecitabine twice daily during radiotherapy. Results: A complete pathologic response (CR) was demonstrated in 12 of 39 patients (31%), while T-downstaging was observed in 24 of 39 patients (63%). N-downstaging was observed in 18 of 28 patients (64%), with a positive node in the CT scan or ultrasound. Two patients with clinical negative nodes were observed in surgical specimens. The results from a univariate analysis indicated that the tumor circumferential extent was less than 50% (p=0.031). Moreover, the length of the tumor was less than 5 cm (p=0.004), while the post-treatment carcinoembryonic antigen (CEA) levels were less than or equal to 3.0 ng/mL (p=0.015) and were significantly associated with high pathologic CR rates. The univariate analysis also indicated that the adenocarcinoma (p=0.045) and radiation dose greater than or equal to 50 Gy (p=0.021) were significantly associated with high T-downstaging, while a radiotherapy duration of less than or equal to 42 days (p=0.018) was significantly associated with N-downstaging. The results from the multivariate analysis indicated that the lesser circumferential extent of the tumor (hazard ratio [HR] 0.150; p=0.028) and shorter tumor length (HR, 0.084; p=0.005) independently predicted a higher pathologic CR. The multivariate analysis also indicated that a higher radiation dose was significantly associated with higher T-downstaging (HR, 0.115; p=0.025), while the shorter duration of radiotherapy was significantly associated with higher N-downstaging (HR, 0.028; p=0.010). Conclusion: The circumferential extent of the tumor and its length was a predictor for the pathologic CR, while radiation dose and duration of radiotherapy were predictors for tumor downstaging. Hence, these factors may be used to predict outcomes for patients and to develop further treatment guidelines for high-risk patients.

• Geotechnical Engineering
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• v.10 no.4
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• pp.29-38
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• 1994

A new method of analyzing downhole seismic data is presented. The method is based upon inverse theory and can be used to resolve wave velocity profiles to a much greater accuracy than possible with conventional analysis methods such as direct or interval measurements. In addition, use of inverse theory permits a rational basis for judging the quality of the velocity profile. Five case studies are presented to illustrate application of the inversion method at various geological formations.