• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.1
• /
• pp.21-28
• /
• 2009

DFT-spread OFDM(Discrete Fourier Transform-Spread Orthogonal Frequency Division Multiplexing) is very effective for solving the PAPR(Peak-to-Average Power Ratio) problem. Therefore, the SC-FDMA(Single Carrier-Frequency Division Multiple Access) which is basically same to the DFT spread OFDM was adopted as the uplink standard of the 3GPP LTE ($3^{rd}$ Generation Partnership Project Long Term Evolution). Unlike the ordinary OFDM system, the SC-FDMA using DFT spreading method is vulnerable to the ICI(Inter-Carrier Interference) problem caused by the phase noise and IQ(In-phase/Quadrature) imbalance and effected FDE(Frequency Domain Equalizer). In this paper, the ICI effects from the phase noise and IQ imbalance which can be problems in uplink transmission are analyzed according the back-off level of HPA. Next, we propose the equalizer algorithm to remove the ICI effects. This proposed equalizer based on the FDE can be considered as up-graded and improved version of PNS(Phase Noise Suppression) algorithm. This proposed equalizer effectively compensates the ICI resulting from the phase noise and IQ imbalance. Finally, through the computer simulation, it can be shown that about SNR=14 dB is required for the $BER=10^{-4}$ after ICI compensation when the back-off is 4.5 dB, $\varepsilon=0.005$, $\phi=5^{\circ}$, and $pn=0.06\;rad^2$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3587-3593
• /
• 2009

Nowadays, the PV systems have been focused on the interconnection between the power source and the grid. The PV inverter, either single-phase or three-phase, can be considered as the core of the whole system because of an important role in the grid-interconnecting operation. An important issue in the inverter control is the load current regulation. In the literature, the Proportional+Integral (PI) controller, normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an ac system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. By comparison with the PI controller, the Proportional+Resonant (PR) controller can introduce an infinite gain at the fundamental ac frequency; hence can achieve the zero steady-state error without requiring the complex transformation and the dq-coupling technique. In this paper, a PR controller is designed and adopted for replacing the PI controller. Based on the theoretical analyses, the PR controller based control strategy is implemented in a 32-bit fixed-point TMS320F2812 DSP and evaluated in a 3kW experimental prototype Photovoltaic (PV) power conditioning system (PCS). Simulation and experimental results are shown to verify the performance of implemented control scheme in PV PCS.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.34 no.3
• /
• pp.220-225
• /
• 2014

Generally, the nonlinearity of ultrasonic waves is measured using a nonlinear parameter ${\beta}$, which is defined as the ratio of the second harmonic's magnitude to the power of the fundamental frequency component after the ultrasonic wave propagates through a material. Nonlinear parameter ${\beta}$ is recognized as an effective parameter for evaluating material degradation. In this paper, we evaluated the nonlinear parameter of Al6061-T6 which had been subjected to an artificial aging heat treatment. The measurement was using the transmitted signal obtained from contact-type transducers. After the ultrasonic test, a micro Vickers hardness test was conducted. From the result of the ultrasonic nonlinear parameter, the microstructural changes resulting from the heat treatment were estimated and the hardness test proved that these estimates were reasonable. Experimental results showed a correlation between the ultrasonic nonlinear parameter and microstructural changes produced by precipitation behavior in the material. These results suggest that the evaluation of mechanical properties using ultrasonic nonlinear parameter ${\beta}$ can be used to monitor variations in the mechanical hardness of aluminum alloys in response to an artificial aging heat-treatment.

• Journal of Animal Science and Technology
• /
• v.50 no.1
• /
• pp.121-132
• /
• 2008

A total of 100 pigs were used to investigate the effects of pig breed on proximate, physicochemical, cholesterol, amino acid, fatty acid and sensory properties of loins. Crossbred pigs were alloted into one of five experimental groups [×Duroc(LYD), ×Berkshire (YBB), British Berkshire(BB), Kagoshima Berkshire(KB), Korean native black pig×Wild boars(KW; Sus coraanus)]. Pigs were slaughtered at 110 kg live weight. Moisture content was significantly(p<0.05) higher in KW than those of other pig breeds. Crude protein content was significantly(p<0.05) higher in YBB and KW than in LYD, BB, and KB. Cholesterol content was significantly(p<0.05) higher in YBB than those of other pig breeds. WHC and pH value had lower and shear force had higher(p<0.05) in YBB than those of other pig breeds. In color, LYD was significantly(p<0.05) higher in L* than those of other pig breeds. There was no significant different in a* and brittleness value among the breeds. In fatty acid and amino acid composition, KW had a higher(p<0.05) UFA/SFA, EFA/UFA ratio and EAA content but lower (p<0.05) SAAA. Total amino acid content was significantly(p<0.05) higher in LYD(20.44%) and BB (20.81%) than those of other pig breeds. In fresh meat, breeds affected meat color, drip loss, marbling score, and overall acceptability(p<0.05). Nevertheless, no significant differences were found among the breeds in the sensory parameters evaluated in the cooked meat, except for flavor

• Journal of Dairy Science and Biotechnology
• /
• v.33 no.4
• /
• pp.237-245
• /
• 2015

The aim of this study was to evaluate physicochemical characteristics of the Mozzarella cheese produced by Streptococcus macedonicus LC743 with immunomodulating activity. The Mozzarella cheese produced by S. macedonicus LC743 has contents of water, protein and fat 53.16%, 53.16% and 20.52%, respectively. In case of nitrogen composition, water soluble nitrogen (WSN), trichloroacetic acid soluble nitrogen (TCASN), phosphotungstic acid soluble nitrogen (PTASN) has the value of 0.384%, 0.051% and 0.060 Nmg/g, respectively. Total amino acid of Mozzarella cheese produced by S. macedonicus LC743 has the higher contents of amino acid than Mozzarella cheese produced by commercial starter except for cysteine. The Mozzarella cheese has immunomodulating activity on IL-$1{\alpha}$, TNF-${\alpha}$, NO with the value of >2,000 pg/mL, 743.38 pg/mL and $8.31{\mu}M$, respectively. The immunomodulating activity of Mozzarella cheese produced by S. macedonicus LC743 was higher than domestic of imported cheese.

• Journal of Food Hygiene and Safety
• /
• v.18 no.4
• /
• pp.189-194
• /
• 2003

Approved chemical preservatives have been widely used to preserve foods and increase their shelf life. There are increasing demends of the partial or complete removal of chemical preservatives from foods vecause of adverse health effect of chemicals. In this study, the possibility of natural antimicrobial compounds, Korean propolis as food preservatives are investigated. Propolis samples were extracted on various concentration of ethanol. Propolis extracts extracted with 100% ethanol showed the highest inhibitory effect aginst food spoilage microorganisms. The 100% ethanol extracts of propolis were selected and the antimicrobial activites of 100% ethanol extracts of proplis against several food spoilage microorganisms were examined. Bacillus subtilis, Micrococcus luteus, Escherichia coli, Staphylcoccus aureus, Bacillus cereus, Shigella sonnei, Salmonella choleraesuis, Erwinia rhapontici, and Vibrio parahaemolyticus as food poisoning microorganisms were chosen for the examination. The Propolis extracts had antimicrobial activity against food spoilage microorganisms. When the microorganisms were treated with propolis extracts, the population of food spolige microorganisms were decreased by 1~9 log.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.4
• /
• pp.71-80
• /
• 2001

In order to evaluate the effectiveness of the organic and natural farming techniques, the actual conditions of the techniques were surveyed and some crops were cultivated in situ. The contents of available $P_2O_5$, exchangeable $Ca^{2+}$ and organic matter of the organic and natural farming soil as well as soil pH were higher than those of the non-organic and non-natural farming soil, and especially the content of organic matter amounting 54.0 g/kg was dominant. Income of the farmers cultivating the different crops with the organic and natural farming was high in order of red pepper in vinyl house > cucumber in vinyl house > fruit(pear) > lettuce in vinyl house > rice. The agricultural materials used in organic and natural farming were ranged from 22 to 25 kinds, representing low pH amounted from 2.9 to 4.5 and low contents of fertilizer ingredients. The expense for purchasing the materials was from three to five times higher than that of soil testing plot. The yields of test crops in the organic and natural farming plots were lower than those of soil testing plot, and the efficiencies of the disease and pest control by the application of the substitutes for pesticide were lower than those by pesticides.

• Journal of the Korean Applied Science and Technology
• /
• v.29 no.2
• /
• pp.330-338
• /
• 2012

During 10 days germination of perilla seeds for sprouts preparation, the changes of proximate composition and antioxidant activities were monitored, and the inhibitory effect of sprouts extracts on perilla oil oxidation was also studied. The moisture content in seeds(2.9%) was increased to 9.2% in sprouts at 10 days while crude ash content wasn't significantly. The crude fat and protein contents were reduced from 46.8% and 20.7% in seeds to 18.2% and 18.3% in sprouts, respectively, but reducing sugar and fiber contents increased from 2.2% and 14.8% to 12.8% and 22.4%, respectively. Compared with perilla leaf, sprouts at 10 days contained more fat, carbohydrate, reducing sugar, and fiber while less moisture, ash, and protein. Antioxidant activities during germination were increased and reached to maximum at 8 days in which Trolox equivalent antioxidant capacity(TEAC) based on DPPH and ABTS radical scavenging were 133.1 and 136.8 Trolox eq. mmol/kg, respectively, and ferric ion reducing power(FRAP) was 399.3 Fe(II) eq. mmol/kg. Polyphenol content(19.2 g/kg) was maximum at this stage, too. Perilla leaf showed similar TEAC but higher FRAP than the sprouts. When methanol extract of sprouts at 8 days was added to perilla oil, the oil oxidation was delayed in dose dependent manner. The induction time for oxidation was extended about 2.8 times by adding 2.5%(w/w) extract, that is, from 1.67 hr(control) to 4.62 hr. This induction time corresponded to 38% level of that of perilla oil containing 2.5% BHT.

• Korean Journal of Soil Science and Fertilizer
• /
• v.21 no.4
• /
• pp.434-442
• /
• 1988

This study has been made to investigate the influences of organic matter on the soil composition, nitrogen fixing organism, soil enzyme activity and nitrogen fixing activity in the paddy rice rhizosphere when rice and barley straw were applied. The results are summarized as follows: 1. The pH in the submerged soil was increased from ear formation stage to harvesting. 2. In the rhizosphere, $Fe^{{+}{+}}$ content was decreased according to the growing stage, while increased in the nonrhizosphere. 3. In the initial stage, rhizosphere was higher than nonrhizosphere but in the late stage nonrhizosphere was higher than rhizosphere on the $NH_4-N$ content. 4. In the submerged soil, rhizosphere was higher than nonrhizosphere, on the concentration of glucose and pentose. 5. Changes of the number of nitrogen fixing organism in whole soil was not high. 6. Generally, rhizosphere was higher than nonrhizosphere on the soil enzyme activity such as phosphatase, ${\beta}$-glucosidase, and protease. 7. Acetylene-reducing activity was the highest in the tillering stage, and rhizosphere, Samgang (high-yielding variety) were higher than nonrhizosphere. Dongjin (general variety) respectively. 8. In the submerged soil applied barley straw, acetylene-reducing activity was slightly higher than rice straw in the initial stage.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.04a
• /
• pp.146.2-147
• /
• 2003

콩 발효식품은 예로부터 단백질 식품원으로서 뿐만 아니라, 식생활에서 없어서는 안되는 매우 중요한 식품 중의 하나였다. 발효식품에 대한 연구가 부진하였던 과거에는 콩 발효식품은 하나의 식품군으로서의 중요성을 가질 뿐 큰 관심의 대상은 아니었다. 그러나 최근에는 많은 연구자들이 콩 발효시 생성되는 기능성 성분 및 생리활성 효과를 점차 밝혀냄으로서 주목을 받기 시작하였다. 따라서 본 실험에서도 콩 발효에 의한 생리활성 효과를 알아보기 위해 Ames법에 의한 항돌연변이원 효과를 실험하였다. 콩 발효는 국산콩을 이용하여 메주에서 분리한 Bacillus sp. 와 Aspergillus sp.를 복합 발효시켜 동결건조 후, 분쇄하여 실험에 사용하였다. 제조된 발효 콩 분말은 일반분석을 행하였으며, 70% 에탄올로 3회 추출하여 감압농축 후, hexane, chloroform ethyl acetate, butanol 및 aqueous로 분획하여 동결 건조시킨 후, S. typhimurium TA98 및 TA100 균주를 이용한 유전자 복귀 돌연변이 시험을 실시하였다. 그 결과, 70% 에탄을 추출물과 각각의 분획물 자체의 돌연변이원성은 없었다. 또한 항돌연변이원 실험에서는 발암물질로서 직접 돌연변이원인 4NQO와 MNNG, 간접 돌연변이원인 Trp-P-1을 이용하였다. 특히 이들 발암물질 중 MNNG(0.4 $\mu\textrm{g}$/plate)의 경우 TA100 균주에서 ehtyl acetate 분획물에서 다른 분획물보다 높은 86.6%의 억제 효과를 나타내었으며, 대부분의 분획물에서도 70%이상의 억제효과를 나타내었다. 또한 각 분획물에서 농도 의존적으로 억제효과 역시 높았으며, 분획물에 따라 서로 다른 억제효과를 나타내었다.아 저장할 때 대비 저온저장고에서는 111일 동안에 11.7%의 중량감모가 발생하였으나, 신기술투입 저온저장고에서는 5.6%의 중량감모만이 발생하여 약 50%의 중량감모를 줄일 수 있었으며, 배의 색깔이나 경도도 대비구 보다 우수하였다. 4. 배를 비닐로 포장하여 대비 저온저장고에 저장한 경우와 비닐로 포장하지 않고 신기술투입 저온저장고에 저장한 경우를 비교할 때 11월~다음해 1월 까지는 중량감모, 과피색깔 및 경도에 큰 차이가 없었으나, 2월부터는 비닐로 포장하여 대비 저온저장고에 저장한 배의 품질변화가 급격히 증가되어 중량감모, 과피색깔 및 경도가 신기술 투입시 보다 급속하게 나빠졌다.를 저장 25일 경과시까지 유지하였다. 수확 시 높은 품온을 갖고 있는 과일을 산지에서 예냉 처리를 한 후 저온 냉장차를 이용하여 유통한다면 관행 유통 구조보다 고품질의 포도를 유통시킬 수 있는 것으로 사료되며 앞으로는 완숙된 고 당도(12.0~15.0Bx)$^{\circ}$ 포도를 수확 한 즉시 예냉 처리하고 저온 유통한다면 보다 신선한 과일을 소비자에게 전달 할 수 있을 것이다.갈변물질이 생성되었다. 이와 같은 결과로 볼 때, BAAG의 처리는 BAAC의 경우보다 가격은 저렴하면서도 항균력은 우수한 천연 항균복합제재로써 농산물 식품원료에 적용하여 선도유지 기간을 연장할 수 있는 효과를 기대할 수 있었다. 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$