• 한국의학물리학회지:의학물리
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• 제32권4호
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• pp.92-98
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• 2021

Purpose: This study automatically discriminates homogeneous and structure edge regions on computed tomography (CT) images, and it evaluates the noise level and edge preservation ratio (EPR) according to the different types of iterative reconstruction (IR). Methods: The dataset consisted of CT scans of 10 patients reconstructed with filtered back projection (FBP), statistical IR (iDose⁴), and iterative model-based reconstruction (IMR). Using the 10th and 85th percentiles of the structure coherence feature, homogeneous and structure edge regions were localized. The noise level was estimated using the averages of the standard deviations for five regions of interests (ROIs), and the EPR was calculated as the ratio of standard deviations between homogeneous and structural edge regions on subtraction CT between the FBP and IR. Results: The noise levels were 20.86±1.77 Hounsfield unit (HU), 13.50±1.14 HU, and 7.70±0.46 HU for FBP, iDose⁴, and IMR, respectively, which indicates that iDose⁴ and IMR could achieve noise reductions of approximately 35.17% and 62.97%, respectively. The EPR had values of 1.14±0.48 and 1.22±0.51 for iDose⁴ and IMR, respectively. Conclusions: The iDose⁴ and IMR algorithms can effectively reduce noise levels while maintaining the anatomical structure. This study suggested automated evaluation measurements of noise levels and EPRs, which are important aspects in CT image quality with patients' cases of FBP, iDose⁴, and IMR. We expect that the inclusion of other important image quality indices with a greater number of patients' cases will enable the establishment of integrated platforms for monitoring both CT image quality and radiation dose.

• 한국포장학회지
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• 제28권3호
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• pp.217-221
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• 2022

저온에서 신선육을 보관 저장하는 용기의 기체조성을 고CO₂/저O₂ 농도로 자동적으로 제어하는 용기 시스템을 제작하고, 0℃에서 21일간 돼지고기 삼겹살을 담아 저장하면서 품질보전의 측면에서 진공 포장과 함기 대조구 조건과 비교하였다. CO₂ 주입 시간 프로그램에 의하여 CO₂ 농도는 47~60%, O₂ 농도는 7~10%로 유지될 수 있었고, 이는 호기적 세균 증식과 pH 증가의 억제의 효과와 함께 관능적 품질유지에 기여하였다. 진공포장은 함기 대조구에 비하여 낮은 미생물 성장과 pH 증가를 보여주었으나 높은 drip 손실의 단점을 보였다. 전체적 품질보존의 측면에서 고안된 고CO₂ 치환 용기는 육류의 품질유지에 효과적이며, 육류의 종류와 특성에 맞게 기체 농도 조건을 변경하여 활용범위를 확장할 수 있을 것이다.

• 한국식품저장유통학회지
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• 제2권2호
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• pp.293-301
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• 1995

Quality changes of Korean native-bee honey were investigated during processing and preseration at different temperature. There were no changes of HMF(Hydroxy methyl furfural) and proline contents, color and diastase activity in Korean native-bee honey, when the honey separated from honey combs at 20$^{\circ}C$ and 40$^{\circ}C$. However, at 50 and 80$^{\circ}C$, browning of Korean native-bee honey was shown, HMF content was increased rapidly and proline content and diastase activity were decreased. There were no changes of chemical composition in Korean native-bee honey during storage at 4$^{\circ}C$ for 6 months. But color was darken and HMF content was increased slowly in Korean native-bee honey during storage at 20$^{\circ}C$. During storage at 30$^{\circ}C$ and 40$^{\circ}C$, HMF content was increased highly, proline content, diastase activity and total acidity was decreased rapidly. It is recommended that Korean native-bee honey is separated from honey comb and purified at less than 40$^{\circ}C$ and stored at 4$^{\circ}C$ through 20$^{\circ}C$.

• 한국정보통신학회논문지
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• 제16권8호
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• pp.1773-1778
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• 2012

최근 들어, 디지털 영상처리 장치에 대한 수요가 급격히 증대되면서 영상의 우수한 화질이 요구되고 있다. 그러나 여러 가지 원인에 의해 잡음이 추가되어 영상을 훼손시킨다. 따라서 잡음제거에 대한 필요성이 대두되고 있으며, 잡음제거 기술은 주요한 연구 분야가 되었다. 영상은 AWGN(additive white Gaussian noise)에 의해 많이 훼손되며, 본 논문에서는 AWGN을 제거하기 위해, 에지보호를 위한 개선된 알고리즘을 제안하였다. 제안한 알고리즘은 먼저 공간거리 차이 정보를 고려한 가중치 필터와 적응 가중치 필터로 처리한 결과값의 평균과 마스크내의 분산과 추정된 잡음분산의 관계식에 의해 처리된 값을 합하여, 영상의 최종출력값을 구한다. 따라서 제안한 방법은 우수한 잡음제거 및 에지보존 특성을 나타내었고 영상의 화질을 개선하였다.

• Reproductive and Developmental Biology
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• 제39권1호
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• pp.7-11
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• 2015

Preservation of liquid semen is an important factor for breeding management in swine industry. Oxidative stress of spermatozoa during liquid preservation has a detrimental effect on sperm quality and decreases fertility. Objective of this study was to determine the effect of antioxidant, Quercetin, on capability of porcine liquid semen preservation. Freshly collected porcine semen from boars (n=3), having proven fertility was counted, diluted to $3{\times}10^7/mL$ and divided into 5 different semen extenders. Aliquots of diluted semen with different extenders were subjected to measure the pH, motility, viability and sperm DNA structure status on elapse time after preservation for 10 days. For the first 3 days, semen preserved in all 5 different extenders maintained their initial pH and either gradually decreased or increased thereafter, indicating lipid peroxidation has started. Sperm motility (r=0.52, p=0.01) and viability (r=0.55, p=0.03) had positive correlation with semen pH. Sperm motility was maintained well (p<0.05) in especially 2 extenders containing Tris and antioxidant compared to other extenders, suggesting both Tris and antioxidant worked as pH regulator and had beneficial effects on sperm characteristic during preservation. Sperm DNA structure status accessed by sperm chromatin structure assay on elapsed time after preservation, tended to be higher in semen preserved without antioxidant. Taken together, addition of antioxidant to extender prevents the sperm from oxidative stress during storage in mechanism by which antioxidant slows the lipid peroxidation, and thus reduced the reactive oxygen species in preserved porcine semen resulted in maintaining semen pH, sperm motility and viability for 7~10 days.

• 한국식품저장유통학회지
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• 제6권2호
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• pp.245-254
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• 1999

Lactic aicd bacteria(LAB)는 전통적으로 식품의 발효과정 중에 사용되는 미생물이다. Lactic acid bacteria를 이용한 bacteriocinogenic culture와 lactic acid bacteria에서 생산되는 산물은 식품의 부패에 원인이 되는 미생물과 병원성균에 대한 생육억제효과을 지니고 있다. 이러한 이유로 생선제품, 유제품. 육제품과 발효되지 않은 냉장식품 등의 식품저장에 lactic acid bacteria를 이용한 연구가 다양하게 수행되어져 오고 있었으나 과실 및 채소류에서의 lactic acid bacteria에 대한 효용가능성에 대해서는 아직까지 광범위하게 연구된 것이 없다. 따라서 lactic acid bacteria의 과일 및 채소류의 저장시 효과적이고 적용성이 넓은 보존제로서의 성공적인 이용을 위해서 식품저장과 lactic acid bacteria에 대한 특성, lactic acid bacteria의 대사산물, lactic acid bacteria의 안정성 등을 고려하여 과일 및 채소의 식품성분 및 구성요소와 미생물의 생육저해효과가 있는 대사산물과의 관계에 대한 많은 연구의 수행이 과일 및 채소제품에서 lactic acid bacteria의 식품보존제로서의 이용가능성을 평가하기 위해 필요한 점으로 사료된다.

• Fisheries and Aquatic Sciences
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• 제23권9호
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• pp.25.1-25.9
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• 2020

Fish is an extremely perishable food product which requires proper handling soon after harvest. The present study was aimed at assessing post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia. Structured and semi-structured questionnaires were used to collect data on post-harvest fish losses and preservation practices from aquaculture producers, artisanal, and commercial fishers. All the fishers who landed on the lakeshore were interviewed, while aquaculture producers were randomly selected based on the information provided by the local department of fisheries. The results of the study revealed that all the fishers experienced post-harvest fish losses at varying degrees with those losing up to 10% of the total catch being in the majority. In contrast, aquaculture producers did not report any post-harvest fish losses. Most aquaculture producers commonly used chilling as preservation practice contrary to artisanal and commercial fishers who commonly used smoking and sun sun-drying respectively. Furthermore, fish product safety and quality control were poorly practiced in the district. Lack of cold storage facilities and fluctuating weather conditions were the major challenges impacting fish post-harvest activities. Therefore, to curb the loss of revenue due to post-harvest fish losses, we propose the introduction of new technology, self-development skills for fishing communities, and enhanced access to refrigeration facilities.

• 한국식품저장유통학회지
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• 제6권1호
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• pp.1-6
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• 1999

Fresh gingers, harvested in Seosan, Choongcheongnam-do, were pre-treated by a washing-pasteurizing-drying process, a curing process, and non-treated, respectively. Then they were stored in a lab-scale storage room(12$^{\circ}C$, >92%RH) to investigate the effect of pre-treatment methods on the quality changes during long-term storage. Weight loss of ginger during storage showed ranges in 0.7∼4.3%, and the weight of gingers pre-treated by washing-drying process showed a tendency to change less than those treated by curing. After storage of 130 days, spoilage rates were about 20% in non-treated, 11% in curing treated, and 12% in washing-drying treated ginger,, showing the effect of pre-treatment. The final rate of sprouting was 13∼15% regardless of treatment methods. The firmness of gingers showed a tendency to decrease in stored ginger for the longer period; however, the values were ranged from 1,200 to 1,400 g/$\textrm{cm}^2$, that is hard enough to show a marketable quality. The contents of reducing sugar showed a tendency to increase with the lapse of storage time.

• 한국식생활문화학회지
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• 제20권1호
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• pp.103-112
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• 2005

The objective of this study was to clarify the effect of addition of green tea powder(0%, 2%, 4%, 6%, 8%) to Yackwa on quality and preservation. Addition of 4% green tea powder turned out to give positive effect on expansion. In test of physical characters, addition of green tea powder had a tendency to lower hardness, cohesiveness, springness and gumminess but to enhance brittleness. Considering the rancidity of oil within Yackwa, addition of green tea powder tended to show lower acid value and peroxide value than non-added treatment but its difference was slight. At the sensory test, surface color, bitterness and green tea flavor were strong but sweet and savory taste weak when green team powder was added(p<0.05). Overall quality appeared to have improved to 5.55 points which is compared to non-addition when the powder was added 4%(p<0.05). In conclusion, 4% addition of green tea powder would be the usefull method to enhance preference and quality of Yackwa.

• 한국식품저장유통학회지
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• 제5권1호
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• pp.49-56
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• 1998

The effects of the water extracts from thyme(TM) and tarragon(TG) on shelf-life and quality of kimchi were investigated by measuring the changes in pH, acidity, number of total microorganisms, number of Lactobacillii and Leuconostoc during fermentation at 1$0^{\circ}C$, and were tested for antimicrobial activities against Lactobacillus plantarum and Leuconostoc mesenteroides. TM and TG were extracted with water, ethyl ether, ethyl acetate and ethanol. Water, ethyl ether, ethyl acetate and ethanol extracts of TM showed antimicrobial activities against Lactobacillus plantarum and did not observed against Leuconostoc mesenteroides. On the other hand, water, ethyl acetate and ethanol extracts of TG showed antimicrobial activities against Leuconostoc mesenteroides and did not observed against Lactobacillus plantarum. The decrease of pH and the increase of acidity showed lower in kimchi prepared by adding water extracts from TM than in products from TG. The number of total microorganisms were also detected less in the kimchi prepared by adding water extracts from TM. And, the properties of barkless of kimchi measured instrumentally were higher for kimchi prepared by adding water extracts from TM, also maintaining good crispness. The optimal addition amounts of both TM and TG for good overall and spicy taste of kimchi were 0.03%. The results suggested the possible use of the extracts of TM and TG can be successfully used for the quality and extension of shelf-life of kimchi.