• Investigative Magnetic Resonance Imaging
• /
• 제21권2호
• /
• pp.82-90
• /
• 2017

Purpose: This study investigated the MRI, MR angiography (MRA) and MR perfusion findings of seizure-related cerebral cortical lesions during the periictal period. Materials and Methods: From a retrospective review of the institutional database between 2011 and 2014, a total of 21 patients were included in this study. Two radiologists assessed periictal MRI, including MRA and MR perfusion, in patients with seizure-related cortical lesions. The parameters examined include: location of cortical abnormality, multiplicity of the affected cortical region, cerebral vascular dilatation, perfusion abnormality and other parenchymal lesions. Results: All patients showed T2 hyperintense cerebral cortical lesions with accompanying diffusion restriction, either unilateral (18/21, 85.7%) or bilateral (3/21, 14.3%). Of the 21 patients enrolled, 10 (47.6%) had concurrent T2 hyperintense thalamic lesions, and 10 (47.6%) showed hippocampal involvement. Of the 17 patients (81%) who underwent MRA, 13 (76.5%) showed vascular dilatation with increased flow signal in the cerebral arteries of the affected cortical regions. On MR perfusion, all 5 patients showed cortical hyperperfusion, corresponding to the region of cortical abnormalities. Conclusion: Seizure-related cerebral cortical lesions are characterized by T2 and diffusion hyperintensities, with corresponding cerebral hyperperfusion and vascular dilatation. These findings can be helpful for making an accurate diagnosis in patients with seizure.

• 한국생산제조학회지
• /
• 제22권3호
• /
• pp.343-348
• /
• 2013

In line with the advances in factory automation, various pieces of equipment are now operated in batch processes controlled by computers. However, many kinds of faults can occur in complicated and large systems, which can result in low productivity and economic loss. The reliability and safety of systems have been studied because of the difficulty of determining the severity and location of faults. Therefore, it is necessary to detect and diagnose such faults in order to guarantee the reliability and safety of the equipment. In this paper, a diagnosis method for the ball bearings of a hydraulic pump is applied using a vibration signal for the maintenance of injection molding equipment. The bearings' defects are selected as a main failure mode through a failure mode and effect analysis (FMEA). Usually, there are nonlinear and impulse components of vibration in a ball bearing with faults. For the effective fault diagnosis of a ball bearing, nonlinear diagnostic methods and time-frequency analysis are applied, in addition to the methods currently used, such as power spectrum, time series analysis, and statistical methods. As a result of this study, a failure diagnosis system is provided that is useful even for non-experts. This is a condition-based method that makes it possible to resolve problems in a timely and economical way, in contrast to the prior method, which required regular but wasteful maintenance based on the experience of expensive external experts.

• Toxicological Research
• /
• 제34권1호
• /
• pp.1-6
• /
• 2018

The purpose of this study was to detect cell death in the liver of mice treated with thioacetamide (TAA) using fluorescence bioimaging and compare this outcome with that using conventional histopathological examination. At 6 weeks of age, 24 mice were randomly divided into three groups: group 1 (G1), control group; group 2 (G2), fluorescence probe control group; group 3 (G3), TAA-treated group. G3 mice were treated with TAA. Twenty-two hours after TAA treatment, G2 and G3 mice were treated with Annexin-Vivo 750. Fluorescence in vivo bioimaging was performed by fluorescence molecular tomography at two hours after Annexin-Vivo 750 treatment, and fluorescence ex vivo bioimaging of the liver was performed. Liver damage was validated by histopathological examination. In vivo bioimaging showed that the fluorescence intensity was increased in the right upper part of G3 mice compared with that in G2 mice, whereas G1 mice showed no signal. Additionally ex vivo bioimaging showed that the fluorescence intensity was significantly increased in the livers of G3 mice compared with those in G1 or G2 mice (p < 0.05). Histopathological examination of the liver showed no cell death in G1 and G2 mice. However, in G3 mice, there was destruction of hepatocytes and increased cell death. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed many cell death features in the liver of G3 mice, whereas no pathological findings were observed in the liver of G1 and G2 mice. Taken together, fluorescence bioimaging in this study showed the detection of cell death and made it possible to quantify the level of cell death in male mice. The outcome was correlated with conventional biomedical examination. As it was difficult to differentiate histological location by fluorescent bioimaging, it is necessary to develop specific fluorescent dyes for monitoring hepatic disease progression and to exploit new bioimaging techniques without dye-labeling.

• 한국멀티미디어학회논문지
• /
• 제10권10호
• /
• pp.1260-1270
• /
• 2007

테스트 기술자들에게 아날로그 회로(또는 혼합신호 회로)의 테스트와 진단은 여전히 어려운 문제여서 이를 해결할 수 있는 효과적인 테스트 방법이 크게 요구된다. 본 논문에서는 time slot specification(TSS) 기반의 내장 전류감지기(Built-in Current Sensor)를 이용한 새로운 아날로그 회로의 테스트 기법을 제안한다. 또한 TSS에 기반 하여 고장 위치를 찾아내고 고장의 종류를 구별해 내는 방법을 제시한다. TSS 기법과 함께 제안하는 내장 전류감지기는 높은 고장 용이도와 높은 고장 검출을 그리고 아날로그 회로내 강고장과 약고장에 대한 높은 진단율을 갖는다. 제안하는 방법에서는 주출력과 전원단자등을 테스트 포인트로 사용하고 전류감지기를 자동 테스트 장치(Automatic Test Equipment)에 구성하므로써 테스트 포인트 선택과정의 복잡도를 줄일 수 있다. 내장 전류 감지기의 디지털 출력은 아날로그 IC 테스트를 위한 내장 디지털 테스트 모듈과 쉽게 연결된다.

• 대한골관절종양학회지
• /
• 제5권1호
• /
• pp.29-34
• /
• 1999

Chondroblastoma is an uncommon neoplasm in bone, occurring at the epiphysis or apophysis of growing long bones and is known to have a recurrence rate of around 10% after surgical treatment. We reviewed 14 patients of pathologically proven chondroblastoma, who were surgically treated, from December 1987 to August 1997. The location of tumors was proximal femur in 4 cases, distal femur in 4 cases, proximal tibia in 2 cases, patella in 1 case, proximal humerus in 1 case and calcaneus in 1 case. The most common complaint was pain. In all nine cases in which MRI was performed, the MR imaging showed a lobulated low signal intensity(SI) rim. Low SI foci within the tumor were present in 4 of 9 cases and corresponded to calcification seen on radiographs or CT. Bone marrow edema was also present in 4 of 9 cases on MR imaging. The average duration of follow-up was 2 years, 5 months, ranging from 1 year to 7 years, 2 months. Twelve patients were treated by curettage and autogenous bone graft, one by curettage only, and one by curettage and bone cementing. Two cases which showed local recurrence were treated with curettage and bone graft. Two recurred cases had the presence of bone marrow edema on MR imaging. The presence or absence of bone marrow edema may be a useful indication of tumor activity, although further study will be required.

• Journal of Korean Neurosurgical Society
• /
• 제29권7호
• /
• pp.891-898
• /
• 2000

Objective : It is difficult to differentiate intramedullary spinal cord tumors preoperatively from non-neoplastic pathologies in patients presenting as non-compressive myelopathies in magnetic resonance imaging(MRI). In this report, the authors reviewed nonneoplastic intramedullary spinal cord lesions preoperatively diagnosed as tumors and discussed their clinical and radiological characteristics and usefulness of surgical intervention. Methods : From January, 1985 to January, 1999, authors experienced eight non-neoplastic pathologies mimicking intramedullary spinal cord tumors and analysed their medical records, radiological findings and histopathological specimens retrospectively. Results : There were five males and three females and the duration of symptoms were from two to 20 months(mean, 9.8 months). The location of lesions were four cervical, one cervicothoracic and three thoracic. All patients manifested sensory abnormality, seven motor weakness, and six bladder symptom. All cases had swollen spinal cords and increased signal intensities in spin-echo sequences. Six cases showed contrast enhancement : four cases were focal and two diffuse. Under the impression of intramedullary tumors, the patients were operated upon. Final diagnoses on the base of clinical and pathologic finding were : three subacute necrotizing myelopathies, two multiple scleroses, two myelopathy of unknown etiology. One case showed no gross abnormality in surgical field in spite of adequate exposure of the lesion, so biopsy was not performed. In that case, postoperative MRI revealed spontaneous resolution of the lesion. Conclusion : MRI is invaluable diagnostic tool in screening myelopathies. However, its high sensitivity and lack of specificity make difficulty in preoperative differential diagnosis of non-compressive myelopathies. Although no surgical morbidity occurred in our series, we sometimes failed to confirm definite diagnosis even with biopsy. In such a circumstance, long-term follow up is needed.

• Journal of Korean Neurosurgical Society
• /
• 제56권2호
• /
• pp.162-165
• /
• 2014

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a chronic, progressive, inflammatory disorder characterized by marked fibrosis of the spinal dura mater with unknown etiology. According to the location of the lesion, it might induce neurologic deficits by compression of spinal cord and nerve root. A 58-year old female with a 3-year history of progressive weakness in both lower extremities was referred to our institute. Spinal computed tomography (CT) scan showed an osteolytic lesion involving base of the C6 spinous process with adjacent epidural mass. Magnetic resonance imaging (MRI) revealed an epidural mass involving dorsal aspect of cervical spinal canal from C5 to C7 level, with low signal intensity on T1 and T2 weighted images and non-enhancement on T1 weighted-enhanced images. We decided to undertake surgical exploration. At the operation field, there was yellow colored, thickened fibrous tissue over the dura mater. The lesion was removed totally, and decompression of spinal cord was achieved. Symptoms improved partially after the operation. Histopathologically, fibrotic pachymeninges with scanty inflammatory cells was revealed, which was compatible with diagnosis of idiopathic hypertrophic pachymeningitis. Six months after operation, motor power grade of both lower extremities was normal on physical examination. However, the patient still complained of mild weakness in the right lower extremity. Although the nature of IHSP is generally indolent, decompressive surgery should be considered for the patient with definite or progressive neurologic symptoms in order to prevent further deterioration. In addition, IHSP can present as an osteolytic lesion. Differential diagnosis with neoplastic disease, including giant cell tumor, is important.

• 한국통신학회논문지
• /
• 제38C권4호
• /
• pp.371-377
• /
• 2013

5톤 이상의 어선에는 VHF(Very High Frequency) 대역의 DSC(Digital Selective Calling)가 어선법과 선박안전법에 의무화되어 있다. 어선의 무선설비 관련 규정에는 안전운항을 확보하고 해양사고 발생시 신속하게 대응하기 위하여 선박의 소유자는 국토해양부장관의 고시에 따라 어선위치 자동발신 장치를 갖추도록 규정하고 있다. 따라서 어업정보통신국은 2012년 동해를 시작으로 남해와 서해에 연차적으로 VHF 해안국을 설치하고, 웹기반으로 리모트 콘트롤 및 모니터링에 의하여 DSC를 원격으로 운용하는 연안 VMS(Vessel Monitoring System) 구축사업이 추진중에 있다. 모든 어선의 VHF DSC는 GPS와 연동되며 DSC의 호출에 의하여 자동으로 위치정보를 중계소에 전송하게 된다. 본 논문에서는 동해권의 VHF DSC 해안국을 대상으로 통신해역 설정과 운용 그리고 등록선박의 항해에 따른 권역별 로밍서비스를 실현하는 항적추적과 RSSI (Received Signal Strength Indication) 기법을 병행하는 알고리즘을 연구하였다.

• 한국산학기술학회논문지
• /
• 제12권8호
• /
• pp.3697-3705
• /
• 2011

동영상의 현재 블록의 움직임 벡터와 이전 블록의 움직임 벡터는 시간적 상관성을 갖고 있다. 본 논문에서는 비디오의 시공간적인 특성과 인접 블록 움직임 벡터의 통계적 특성을 이용하는 새로운 예측 탐색 알고리즘을 제안한다. 제안된 ANBA는 이전 프레임과 현재 프레임의 인접 블록의 움직임 벡터들의 평균값으로 구한 후보 벡터와 현재 블록의 이전 시점의 움직임 벡터의 2개의 후보 벡터 중에서 가장 작은 SAD 값을 갖는 점을 정확한 움직임 벡터를 찾기 위한 초기 탐색점 위치로 결정한다. 실험 결과 제안된 방식은 MVFAST와 PMVFAST에 비해 PSNR 값에 있어서 평균적으로 0.01~0.64dB 개선되고 영상에 따라 최고 1.06dB 정도 우수한 결과를 나타내었다.

• 비파괴검사학회지
• /
• 제27권2호
• /
• pp.157-163
• /
• 2007

본 연구에서는 광섬유 케이블을 이용한 콘크리트 구조물의 균열 탐사 방법을 개발하였다. 광통신 분야에서 광섬유 케이블의 손상을 탐지하기 위해 널리 사용하고 있는 광신호 분석기인 OTDR과 일반 통신용 광섬유 케이블을 사용하여 콘크리트의 표면 및 내부에 발생한 균열의 탐사 실험을 수행하였다. 콘크리트가 균열 하중에 부과되어 초기 균열을 발생시킬 때 미리 부착된 광섬유가 균열의 위치에서 균열 거동을 함께 함으로써 손상을 입게 되어 균열의 발생 유무와 위치를 찾고자 하였다. 균열을 탐사하는데 있어 광섬유의 탈피 정도가 균열 탐사 여부를 결정짓는 가장 주요한 인자라고 파악하였으며, 예비 실험을 포함한 4차례의 실내 검증 실험을 통하여 균열을 탐사할 수 있었다. 이 연구 결과는 콘크리트 구조물의 균열 관리와 유지관리 차원으로의 활용도가 크다고 판단된다.