• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.7-13
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• 2000

Purpose : To assess the distortion of MRI with the Leksell stereotactic radiosurgery system in variable pulse sequence and imaging plane through phantom study, to find most adequate imaging plane and pulse sequence for stereotactic radiosurgery system. Materials and methods : We made the phantoms for MRI and get images in variable conditions and analyzed the image distortion using image analysis program, and statistically using paired student t-test. Results : The transeverse plane images had acceptable error ranges bless than 1.5mm) in all pulse sequence in both the analysis of fiducial marker in stereotactic G-frame and the phantom study. The coronal plane images had unacceptable large errors (more than 1.7mm) in the analysis of fiducial marker in the stereotactic G-frame, but had corrected small errors (less than 1.5mm) in the phantom study. Conclusion : We find from the phantom study that the present MR machines are adequate for stereotactic surgery system in frequently used pulse sequences, and imaging planes.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.35-43
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• 2004

In this paper, we proposed a vehicle recognition and electronic toll collection system with detection and classification of vehicle identification mark and emblem as well as recognition of vehicle license plate to unman toll fee collection system or incoming/outcoming vehicles to an institution. In the proposed algorithm, we first process pre-processing step such as noise reduction and thinning from the rear side input image of vehicle and detect vehicle mark, emblem and license plate region using intensity variation informations, template masking and labeling operation. And then, we classify the detected vehicle features regions into vehicle mark and emblem as well as recognize characters and numbers of vehicle license plate using hybrid and seven segment pattern vector. To show the efficiency of the proposed algorithm, we tested it on real vehicle images of implemented vehicle recognition system in highway toll gate and found that the proposed method shows good feature detection/classification performance regardless of irregular environment conditions as well as noise, size, and location of vehicles. And also, the proposed algorithm may be utilized for catching criminal vehicles, unmanned toll collection system, and unmanned checking incoming/outcoming vehicles to an institution.

• Journal of the KSME
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• v.34 no.10
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• pp.764-769
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• 1994

본 연구에서 개발한 KARV-2의특징은 저가의 소형시스템이다. 4인승 소형지프차에 모든 컨트 롤시스템을 장착하고도 외부에 별로 표가 나지 않을 정도임에도 그 성능 면에서는 고속도로를 자율주행할 수 있다는 점이다. 첨단기술의 개발과 더불어 이 차량의 성능도 계속 개선될 것이다. 언젠가는 궤도 위를 달리는 기차와 같이 정확하고 안전하게 주행할 수 있어, 탑승자는 마음놓고 그저 신문을 읽거나 음료수를 마시면서 스쳐 가는 경관을 즐길 수 있는 시기가 곧 도래할 것 으로 믿는 다. 이를 위하여는 차량작동의 신뢰도 향상이 절대 전제조건이다. 앞으로는 일기조건 이나 주야에 관계없이 마치궤도 위를 달리는 기차처럼 안전하게 주행할 수 있는 시스템의 개발이 필요하다. 또한 고속도로가 아닌 시내주행을 위해서는 노면표식인식, 도로표지판 인식, 신호등 인식 등 해결되어야 할 문제들이 산적해 있는 상황이다.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1146-1149
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• 2014

To discriminate polarities of stator windings for 3 phase induction motors terminal tags of which are not readable, it is possible to utilize the residual magnetic flux present at their rotors as well as to use the way based on external exciting current. The induced voltages are basically decided by parameters such as the quantity of residual flux, the rotator speed by hand force and the phase properties between stator windings. To adopt induced voltages by residual flux for polarity discrimination at sites, the measured voltages by multi-testers need to be readable in magnitude enough to discriminate winding condition with reasonable phase characteristics. This study focuses on the analysis of various connection cases in the expectation that the summing voltages induced by residual flux shall show zero in case of normal connections while the sum becomes greater indication if the connection is in wrong condition. The proposed method is applied to actual motors to disclose how effective it is for polarity discrimination at sites through comparison of output signals between normal and fault connections.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1555-1562
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• 2000

Objects : Surgical management of the distal anterior cerebral artery(DACA) aneurysms presents several unique problems to surgeons, such as difficulty in early identification of parent arteries, high incidence of rebleeding and premature rupture, and requirement of unfamiliar approach other than conventional frontotemporal craniotomy. Therefore, preoperative anatomical knowledge of anterior interhemispheric fissure and entry point of dissection is prerequisite. Authors utilized a frontobasal approach for DACA aneurysms by using consistent external landmark for guidance to the deep structure. Materials and Methods : From Nov. 1995 to Jun. 1999, a surgical clipping of DACA aneurysms was carried out in 9 patients among a total 131 patients with intracranial aneurysms. In each case, the clinical and aneurysmal features were carefully reviewed through the angiograms, medical records, and intraoperative findings. Results : The incidence of DACA aneurysms was 6.9% from our series. All cases were arisen from juxtacallosal por-tion ; 6 cases from pericallosal-callosomarginal(PC-CM) junction and 3 from pericallosal-frontopolar(PC-FP) junction. Associated vascular anomalies were noted in 3 cases and multiple aneurysms in 3 cases, respectively. The preoperative clinical grades were generally poor. An early surgery was performed in 7 cases and frontobasal interhemispheric approaches in 7 cases. Postoperatively, two patients died of complications ; one delayed ischemic vasospasm and one aspiration pneumonia but remaining patients recovered well. Conclusion : The frontobasal interhemispheric approach was useful for DACA aneurysms in early surgery. Division of superior sagittal sinus(SSS) enabled a minimal retraction of brain on both sides, and prevention of intraoperative rupture was possible. Authors suggest the frontopolar(first frontal bridging) vein as a constant external landmark for approaching the genu of the corpus callosum and juxtacallosal DACA aneurysms.

• The KIPS Transactions:PartA
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• v.14A no.2
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• pp.77-84
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• 2007

The intima media thickness(IMT) of the carotid artery from B mode ultrasound images has recently been proposed as the most useful index of individual atherosclerosis and can be used to predict major cardiovascular events. Ultrasonic measurements of the IMT are conventionally obtained by manually tracing interfaces between tissue layers. The drawbacks of this method are the inter and intra observer variability and its inefficiency. In this paper, we present a multiresolution snake method combined with the dynamic programming, which overcomes the various noises and sensitivity to initialization of conventional snake. First, an image pyramid is constructed using the Gaussian pyramid that maintains global edge information with smoothing in the images, and then the boundaries are automatically detected in the lowest resolution level by minimizing a cost function based on dynamic programming. The cost function includes cost terms which are representing image features and geometrical continuity of the vessel interfaces. Since the detected boundaries are selected as initial contour of the snake for the next level, this automated approach solves the problem of the initialization. Moreover, the proposed snake improves the problem of converging th the local minima by defining the external energy based on multiple image features. In this paper, our method has been validated by computing the correlation between manual and automatic measurements. This automated detection method has obtained more accurate and reproducible results than conventional edge detection by considering multiple image features.

• Progress in Medical Physics
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• v.19 no.4
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• pp.241-246
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• 2008

Patient's respiration can have an effect on movement of tumor range and peripheral organs. Therefore, the respiratory signal was acquired by relation between external markers and movement of patient's abdomen during radiational therapy in order to minimize the effect of respiration. Based on this technique, many studies of rational therapy to irradiate at particular part of stable respiratory signals have executed and they have been clinically applied. Nevertheless, the phase-based method is preferred to the amplitude-based method for the rational therapy related to respiration. Because stabilization of the respiratory signal are limited. In this study, a in-house respiratory signal analysis program was developed for the phase reassignment and the analysis of the irregular respiratory signals. Various irregular respiratory patterns was obtained from clinical experimental volunteers. After then, the in-house program analyzed the factors affecting to phase assignment which is directly related to irradiated sector. Subsequently, accuracy of phase assignment was improved with removement of irregular signals by self-developed algorithm. This study is considered to be useful for not only image reconstruction and elevation of irradiating accuracy through phase assignment of RPM system but also analysis of respiratory signals. Moreover, development of 4D CT image is planed with phantom researches or clinical experiments based on this program.

• Journal of Life Science
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• v.18 no.3
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• pp.381-386
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• 2008

Deep sea water was tested for cancer chemopreventive activity by measuring the activities of ${\beta}-$ naphthoflavone $({\beta}-NF)-induced$ cytochrome P 450 1A2 (CYP 1A2), quinone reductase (QR) and glutathione-S-transferase (GST), glutathione (GSH) levels, and ornithine decarboxylase (ODC) activity. The in vitro incubation of rat liver microsome with deep sea water (a hardness range of $100{\sim}1,000$) showed a hardness-dependent inhibition of CYP 1A2 activity. QR and GST activities were induced about $1.1{\sim}1.2$ fold with the treatment of deep sea water in murine hepatoma Hepa 1clc7 cells. In addition GSH levels were increased $1.3{\sim}1.4$ fold in a hardness range of $100{\sim}1,000$. The deep sea water showed 20.3 and 35.0% inhibition of 12-O- tetradecanoylphorbol-13-a-cetate (TPA)-induced ODC activity at hardness 800 and 1,000, respectively. Therefore, deep sea water is worth further investigation with respect to cancer chemoprevention or therapy.