• Korean Journal of Microbiology
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• v.28 no.3
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• pp.219-228
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• 1990

A kanamycin resistance($Km^r$) gene was studied for its transfer in natural freshwater environments by using the natural bacterial isolate(M1) of DK1 and the DKC601 strain, $Km^r$ plasmid of which was genetically engineered from the NI strain. The transfer frequency ofthe $Km^r$ gene and rearrangement of the $Km^r$ plasmid were compared between the gnetically engineered microorganism(GEM) and the NI parental strain by conjugation with the same recipient strain. The transfer frequency of the $Km^r$ gene was about $9.1\times 10^{-12}-1.8\times 10^{-11}$ in both the GEM and NI strains at 5 to $10^{\circ}C$, but the frequency of the NI was about 10 times higher than that of the GEM at 20 to $30^{\circ}C$. The $Km^r$ plasmid in the transconjugants obtained by conjugation of the NI with the MY1 strain as a ricipient showed alot of rearrangement, but the $Km^r$ plasmid transferred from the GEM was stable without alteration of its size. When the MT2 strain was used as a recipient, however, such a rearrangement of the $Km^r$ plamid was observed in the transconjugants obtained from the GEM as well as the NI strain. In those transconjugants obtained from different mating pairs and water environments, the plasmid were appeared to decrease in their number as the period of conjugation time was prolonged, but only the $Km^r$ plasmid transferred from the GEM kept having its size of 52kb. Therefore, the $Km^r$ gene was transferred at the same rate from the GEM and NI strains in natural freshwater environment, but the gene of the GEM strain was more stable than the NIduring conjugation and the $Km^r$ plasmid was rearranged by changing the recipient strain for conjugation in any water environments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.95-101
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• 2007

The synthesis of NaA zeolite membrane on a porous alumina support from clear solution by using hydrothermal reaction was investigated. Effects of reaction temperature, reaction time and seeding for transformation of zeolite A membrane and powder which are produced in the reactor were monitored through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The transformation process of producing Zeolite A membrane starts from the formation of the compact and continuous membrane on the surface of porous support from clear solution. The large Zeolite A poly-crystal was then farmed through the dissolution process. Finally, the process was advanced from sodalite to amorphous. In case of powder, sodalite is formed in the early stage of reaction because of surrounding space difference between membrane and powder crystal. Discrete surrounding space of powder crystal makes easy to transform to sodalite. From Zeolite A to amorphous through transformed product was rapidly advanced at high temperature while the membrane with somewhat low coverage was obtained at low temperature. A compact and continuous zeolite A membrane was synthesized at $120^{\circ}C$ in 12-hour period.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.30-41
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• 2007

Purpose: Bone metastasis in breast cancer patients are usually assessed by conventional Tc-99m methylene diphosphonate whole-body bone scan, which has a high sensitivity but a poor specificity. However, positron emission tomography with $^{18}F-2-deoxyglucose$ (FDG-PET) can offer superior spatial resolution and improved specificity. FDG-PET/CT can offer more information to assess bone metastasis than PET alone, by giving a anatomical information of non-enhanced CT image. We attempted to evaluate the usefulness of FDG-PET/CT for detecting bone metastasis in breast cancer and to compare FDG-PET/CT results with bone scan findings. Materials and Methods: The study group comprised 157 women patients (range: $28{\sim}78$ years old, $mean{\pm}SD=49.5{\pm}8.5$) with biopsy-proven breast cancer who underwent bone scan and FDG-PET/CT within 1 week interval. The final diagnosis of bone metastasis was established by histopathological findings, radiological correlation, or clinical follow-up. Bone scan was acquired over 4 hours after administration of 740 MBq Tc-99m MDP. Bone scan image was interpreted as normal, low, intermediate or high probability for osseous metastasis. FDG PET/CT was performed after 6 hours fasting. 370 MBq F-18 FDG was administered intravenously 1 hour before imaging. PET data was obtained by 3D mode and CT data, used as transmission correction database, was acquired during shallow respiration. PET images were evaluated by visual interpretation, and quantification of FDG accumulation in bone lesion was performed by maximal SUV(SUVmax) and relative SUV(SUVrel). Results: Six patients(4.4%) showed metastatic bone lesions. Four(66.6%) of 6 patients with osseous metastasis was detected by bone scan and all 6 patients(100%) were detected by PET/CT. A total of 135 bone lesions found on either FDG-PET or bone scan were consist of 108 osseous metastatic lesion and 27 benign bone lesions. Osseous metastatic lesion had higher SUVmax and SUVrel compared to benign bone lesion($4.79{\pm}3.32$ vs $1.45{\pm}0.44$, p=0.000, $3.08{\pm}2.85$ vs $0.30{\pm}0.43$, p=0.000). Among 108 osseous metastatic lesions, 76 lesions showed as abnormal uptake on bone scan, and 76 lesions also showed as increased FDG uptake on PET/CT scan. There was good agreement between FDG uptake and abnormal bone scan finding (Kendall tau-b : 0.689, p=0.000). Lesion showed increased bone tracer uptake had higher SUVmax and SUVrel compared to lesion showed no abnormal bone scan finding ($6.03{\pm}3.12$ vs $1.09{\pm}1.49$, p=0.000, $4.76{\pm}3.31$ vs $1.29{\pm}0.92$, p=0.000). The order of frequency of osseous metastatic site was vertebra, pelvis, rib, skull, sternum, scapula, femur, clavicle, and humerus. Metastatic lesion on skull had highest SUVmax and metastatic lesion on rib had highest SUVrel. Osteosclerotic metastatic lesion had lowest SUVmax and SUVrel. Conclusion: These results suggest that FDG-PET/CT is more sensitive to detect breast cancer patients with osseous metastasis. CT scan must be reviewed cautiously skeleton with bone window, because osteosclerotic metastatic lesion did not showed abnormal FDG accumulation frequently.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.125-134
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• 2010

It is occurred bus arrival time errors when a bus arrives at a bus stop because of a variety of traffic condition such as traffic signal cycle, the time to get on and off a bus, a bus-only lane and so on. In this paper, bus delay time which is occurred as the result of traffic condition was estimated with Markov Chain process and bus arrival time at each bus stop was predicted with it. As the result of the study, it is confirmed to improve accuracy than the method of bus arrival time prediction with existing method (weighed moving average method) in case predicting bus arrival time using 7 by 7 and 9 by 9 matrixes.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.177.1-177.1
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• 2011

국내 바이오디젤의 원료로 사용되는 식물성 오일은 거의 전량이 수입된 것으로 원료를 자급화 하기 위한 방안으로 국내 동물성 폐자원을 이용한 바이오디젤 연구가 활발히 진행되고 있다. 본 연구에서는 전자레인지를 이용해 동물성 폐자원인 폐돈지 및 폐우지로부터 오일을 추출 후 물성을 분석하고 전이에스테르화 반응을 진행하였으며 바이오디젤 제조 특성을 조사하고자 하였다. 전이에스테르화 반응에 사용되는 염기 촉매를 몇가지 선정하여 각각의 촉매에 따른 바이오디젤의 반응특성을 메탄올 양을 변화시키며 조사 실험하였다. 기존에 사용된 바이오디젤 제조 촉매는 KOH를 주로 사용하였으며 본 연구에서는 KOH, NaOH, $NaOCH_3$를 촉매로 사용하여 오일질량 대비 0.8~1.2%의 촉매를 사용하였으며 메탄올의 양은 오일 몰수 대비 6:1~12:1의 비율로 사용하여 반응시간에 따른 반응특성과 제조 바이오디젤의 물성을 분석해 각 촉매에 따른 바이오디젤 생산 특성을 비교분석하였다.

• 대한위암학회:학술대회논문집
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• 2002.10a
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• pp.11-18
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• 2002

위암의 진단에서 CT스캔은 수술 전 병기결정이나 수술 후 추적검사에서 필수적인 검사방법으로 인정을 받고 있고, 보편적으로 가장 많이 유용되고 있다. 그러나 나선식 CT를 사용하고 여러 가지 스캔방법의 개선에도 불구하고, 인접장기로의 직접침윤, 작은 크기의 간전이의 발견, 정상 크기범위의 림프절에서 전이의 발견, 양성 림프절과 전이의 감별, 복막전이에 대한 평가에서 지금까지의 보고들은 만족스러운 결과를 얻지 못하고 있으며 CT의 한계점으로 남아 있다. 그러나 최근에는 나선식 CT보다 더 빠른 시간내 더 얇은 두께의 절편을 얻을 수 있고, 이를 이용하여 관상면 및 시상면으로 정밀하게 재구성하거나 3D영상을 얻을 수 있는 다검출식 나선식 CT가 개발되어 사용되고 있고, CT 진단의 정확도를 높일 것으로 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.708-711
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• 2016

본 논문에서는 의료초음파 영상에서 진단 파라미터 데이터를 가시화 하는 방법론으로서 연속적인 픽셀 값을 갖는 전이시간 데이터의 표현과, 4가지 유형의 값으로 분류되는 병변 진단 파라미터 영상을 생성하는 방법을 제시한다. 또한 생성된 파라미터 영상에서 노이즈를 제거하기 위한 방법론으로서 MRF 모델을 이용한 영상개선 기법을 제안한다. 이러한 파라미터 영상 생성기법은 초음파 진단 데이터에서 조영증강 패턴의 동적인 변화에 대한 육안 판별의 한계를 극복할 수 있게 한다. MRF 기반 영상개선 과정에서 연속적인 픽셀 값에 대한 에너지함수를 정의하고 이를 최적화 하는 기법을 개발하였으며 실제 의료영상을 사용한 실험을 통하여 제안된 이론의 유용성을 평가하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.70-71
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• 2017

Volunteer Computing은 대규모 프로젝트를 많은 분산된 데스크탑, 랩탑 PC, 그리고 스마트 폰과 같은 모바일 디바이스의 idle(유휴 상태)인 컴퓨팅 자원을 기여(Volunteer)받아 수행하는 환경이다. 그러나 기여된 컴퓨팅 자원이 idle과 used(사용 상태) 간의 상태전이가 빈번히 일어나거나, idle로 지속되는 시간이 짧은 자원의 경우, 프로젝트를 수행하는데 비효율적이다. 따라서 본 논문에서는 이러한 자원을 구분하고, 해당 자원의 다음 상태전이확률테이블을 계산하여 결과에 따라 해당 자원에 적합한 작업을 할당하는 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.232-235
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• 2013

간 질환 진단을 위한 의료 초음파 동영상에서 호흡으로 인한 영상의 흔들림 현상은 전이시간(transit time) 요소와 같은 진단 파라미터의 신뢰도를 저하시킬 뿐만 아니라, 정확한 병변 형태의 추출을 어렵게 한다. 본 연구에서는 호흡 주기를 자동으로 감지하고 이를 기반으로 ROI 를 추적하는 방법과 프레임 샘플링을 통하여 TIC(Time-Intensity Curve) 형태의 왜곡을 보정하는 방법을 고찰한다. 세부적으로 동적 가중치와 모멘텀 요소를 고려한 추적 기법을 제시하고 유용성을 평가한다. 또한 호흡주기와 프레임간 유사도(similarity)를 기반으로 한 영상 샘플링 기법을 제안하고 이로부터 신호의 왜곡을 보정할 수 있음을 보인다.

• The Transactions of the Korea Information Processing Society
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• v.13 no.2
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• pp.41-47
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• 2024

When there were disparities in performance between models trained in the time and frequency domains, even after conducting an ensemble, we observed that the performance of the ensemble was compromised due to imbalances in the individual model performances. Therefore, this paper proposes a leakage detection technique to enhance the accuracy of pipeline leakage detection through a step-wise learning approach that extracts features from both the time and frequency domains and integrates them. This method involves a two-step learning process. In the Stage 1, independent model training is conducted in the time and frequency domains to effectively extract crucial features from the provided data in each domain. In Stage 2, the pre-trained models were utilized by removing their respective classifiers. Subsequently, the features from both domains were fused, and a new classifier was added for retraining. The proposed transfer learning-based feature fusion technique in this paper performs model training by integrating features extracted from the time and frequency domains. This integration exploits the complementary nature of features from both domains, allowing the model to leverage diverse information. As a result, it achieved a high accuracy of 99.88%, demonstrating outstanding performance in pipeline leakage detection.