• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.126-133
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• 2003

High performance induction motor drives are driven by two advanced control methods: vector control and direct torque control (DTC). In order to apply the control methods to the speed/position control systems, the informations on rotor speed and rotor or stator flux are required. The speed is measured by encoder, and the rotor or stator flux is estimated by using the motor parameters and measured currents. The control input generated on the basis of the information that is provided by abnormal sensors should be far from the desired value and deteriorates the overall control perfonnance. In this paper, the effects of sensor faults on the motor variables and the control performance of induction motor drives are analyzed by both theoretical approach and simulation study. The presented analysis results could be utilized for the purpose of developing a fault detection and isolation scheme in induction motor drives.

• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1709-1722
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• 2022

The rise in temperature induced by global warming caused in El Nino and La Nina, and abnormally changed the temperature of seawater. Rainfall concentrates in some locations due to abnormal variations in seawater temperature, causing frequent abnormal floods. It is important to rapidly detect flooded regions to recover and prevent human and property damage caused by floods. This is possible with synthetic aperture radar. This study aims to generate a model that directly derives flood-damaged areas by using modified U-NET and TerraSAR-X images based on Multi Kernel to reduce the effect of speckle noise through various characteristic map extraction and using two images before and after flooding as input data. To that purpose, two synthetic aperture radar (SAR) images were preprocessed to generate the model's input data, which was then applied to the modified U-NET structure to train the flood detection deep learning model. Through this method, the flood area could be detected at a high level with an average F1 score value of 0.966. This result is expected to contribute to the rapid recovery of flood-stricken areas and the derivation of flood-prevention measures.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.116-122
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• 2016

Recently, the production cycle in manufacturing process has been getting shorter and different types of product have been produced in the same process line. In this case, the control chart using coefficient of variation would be applicable to the process. The theory that random variables are located in the three times distance of the deviation from mean value is applicable to the control chart that monitor the process in the manufacturing line, when the data of process are changed by the type of normal distribution. It is possible to apply to the control chart of coefficient of variation too. ${\bar{x}}$, s estimates that taken in the coefficient of variation have just used all of the data, but the upper control limit, center line and lower control limit have been settled by the effect of abnormal values, so this control chart could be in trouble of detection ability of the assignable value. The purpose of this study was to present the robust control chart than coefficient of variation control chart in the normal process. To perform this research, the location parameter, ${\bar{x_{\alpha}}}$, $s_{\alpha}$ were used. The robust control chart was named Tim-CV control chart. The result of simulation were summarized as follows; First, P values, the probability to get away from control limit, in Trim-CV control chart were larger than CV control chart in the normal process. Second, ARL values, average run length, in Trim-CV control chart were smaller than CV control chart in the normal process. Particularly, the difference of performance of two control charts was so sure when the change of the process was getting to bigger. Therefore, the Trim-CV control chart proposed in this paper would be more efficient tool than CV control chart in small quantity batch production.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2051-2055
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• 2014

Background: To evaluate the performance of Siriraj liquid-based cytology (LBC) for cervical neoplasia screening after increasing use of this technology. Materials and Methods: Cytological reports of 103,057 Siriraj-LBC specimens obtained in 2007-2009 were compared with those of 23,676 specimens obtained in 2006. Results: Comparing with the year 2006, the 2007-2009 patients were slightly older ($43.4{\pm}12.yr$ vs $42.7{\pm}12.2yr$, p <0.001), and their specimens had much lower proportion of unsatisfactory slides (OR=0.06, 95%CI 0.04-0.09) with comparable detection rates (3.96% vs 3.70%, p=0.052) but different proportions of various cytological abnormalities (p<0.001). The 2007-2009 Siriraj-LBC had a negative predictive value (NPV) for cervical intraepithelial neoplasia 2+ (CIN2+) of 97.6% and an overall positive predictive value (PPV) of 43.9%. The PPV for CIN2+ varied with types of abnormal cytology, from 13.7% to 93.8% in atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), atypical squamous cells cannot exclude HSIL (ASC-H), high-grade squamous intraepithelial lesion (HSIL), atypical glandular cells (AGC), to squamous cell carcinoma (SCC), respectively. The PPVs for CIN2+ in ASCUS and LSIL were comparable, but the PPV for CIN1 was higher for LSIL than for ASCUS (41.63% vs 16.32%). Conclusions: Siriraj-LBC has demonstrated a stable detection rate and NPV for CIN2+ of >95% since the first year of use. The comparable PPVs for CIN2+ of ASCUS and LSIL suggests that these two conditions may undergo similar management; other cytological abnormalities need immediate evaluation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.250-257
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• 2011

This experiment present the automatic detection algorithm of gastric cancer that take second place among all cancers. If an inflammation and a cancer are not examined carefully, early ones have difficulty in being diagnosed as illnesses than advanced ones. For diagnosis of gastric cancer, and progressing cancer in this study, present 4 algorithm. research team extracted an abnormal part in stomach through the endoscope image. At first, decide to use shading technique or not in each endoscope image for study. it make easy distinguish to whether tumor is existing or not by putting shading technique in or eliminate it by the color. Second. By passing image subjoin shading technique to erosion filter, eliminate noise and make give attention to diagnose. Third. Analyzing out a line and fillet graph from image adding surface shade and detect RED value according to degree of symptoms. Fourth. By suggesting this algorithm, that making each patient's endscope image into subdivision graph including RED graph value, afterward revers the color, revealing the position of tumor, this study desire to help to diagnosing gastric, other cancer and inflammation.

• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.119-128
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• 2000

Purpose: The aim of this study was to investigate the diagnostic role of $^{99m}Tc$-Tetrofosmin in detection of breast cancer and compared with that of $^{99m}Tc$-MIBI. Material and Methods: Forty-eight patients with a clinically palpable mass or abnormal mammographic or ultrasonographic findings had $^{99m}Tc-MIBI\;and\;^{99m}Tc$-Tetrofosmin scintimammographies after intravenous injection of 925 MBq of radiopharmaceuticals. The scintimammographs were correlated with histopathologic findings. Results: Thirty-three patients were diagnosed with breast cancer and 15 patients with benign breast diseases. The numbers of true positive, true negative, false positive, and false negative cases of $^{99m}Tc$-MIBI scintimammography were 29, 10, 5, and 4 respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of $^{99m}Tc$-MIBI scintimammographies were 87.8%, 66.7%, 85.3%, and 71.4% respectively. The numbers of true positive, true negative, false positive, and false negative cases of $^{99m}Tc$-Tetrofosmin were 31,10, 5, and 2 respectively. The sensitivity, specificity, positive predictive value, negative predictive value of $^{99m}Tc$-Tetrofosmin were 93.9%, 66.7%, 86.1%, and 73.3% respectively. One patient was false negative in both $^{99m}Tc-MIBI\;and\;^{99m}Tc$-Tetrofosmin acintimammographies and its size was 0.5 cm. Conclusion: $^{99m}Tc-Tetrofosmin\;and\;^{99m}Tc-MIBI$ were non-invasive and useful in detection of breast cancer and $^{99m}Tc$-Tetrofosmin was comparable to the $^{99m}Tc$-MIBI in detection of primary breast cancer.

• Tuberculosis and Respiratory Diseases
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• v.40 no.1
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• pp.72-78
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• 1993

Background: In malignancies, detection of metastatic foci is of value in making therapeutic plans for treatment of disease and prevention of life-threatening complications. Common sites for metastasis of bronchogenic cancer include lymph nodes, liver, brain, adrenals and bone. Skull, vertebrae, ribs and long bones are common sites for bone metastasis. But in epidermoid carcinoma, the incidence of bone metastasis is relatively low and especially to the distal phalangeal bone is rare. Methods: We experienced a case of epidermoid carcinoma with the first distant metastasis to the fifth distal phalangeal bone, right toe. Results: The initial stage in the diagnosis of epidermoid carcinoma was T4N3MO. During the third round of anticancer chemotherapy, we recognized the distant metastasis to the fifth distal phalangeal bone for the first time. Localized abnormal findings were noted by bone X-ray and scanning. By a histopathologic examination of the amputated toe, we confirmed the metastasis of epidrmoid bronchogenic carcinoma. Conclusion: If localized abnormal finding is discovered at an unusual site for metastasis, we recommend physicians to consider the possibility of metastasis even though it is very low.

• Journal of Biomedical Engineering Research
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• v.27 no.5
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• pp.203-209
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• 2006

The aim of this study is to investigate the feasibility of ex vivo MR diffusion tensor imaging technique in order to observe the diffusion-contrast characteristics of human gastric tissues. On normal and pathologic gastric tissues, which have been fixed in a polycarbonate plastic tube filled with 10% formalin solution, laboratory made 3D diffusion tensor Turbo FLASH pulse sequence was used to obtain high resolution MR images with voxel size of $0.5{\times}0.5{\times}0.5mm^3\;using\;64{\times}32{\times}32mm^3$ field of view in conjunction with an acquisition matrix of $128{\times}64{\times}64$. Diffusion weighted- gradient pulses were employed with b values of 0 and $600s/mm^2$ in 6 orientations. The sequence was implemented on a clinical 3.0-T MRI scanner(Siemens, Erlangen, Germany) with a home-made quadrature-typed birdcage Tx/Rx rf coil for small specimen. Diffusion tensor values in each pixel were calculated using linear algebra and singular value decomposition(SVD) algorithm. Apparent diffusion coefficient(ADC) and fractional anisotropy(FA) map were also obtained from diffusion tensor data to compare pixel intensities between normal and abnormal gastric tissues. The processing software was developed by authors using Visual C++(Microsoft, WA, U.S.A.) and mathematical/statistical library of GNUwin32(Free Software Foundation). This study shows that 3D diffusion tensor Turbo FLASH sequence is useful to resolve fine micro-structures of gastric tissue and both ADC and FA values in normal gastric tissue are higher than those in abnormal tissue. Authors expect that this study also represents another possibility of gastric carcinoma detection by visualizing diffusion characteristics of proton spins in the gastric tissues.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.10039-10043
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• 2014

Background: In Pakistan thyroid cancer is responsible for 1.2% cases of all malignant tumors. Ultrasonography (US) is helpful in detecting cancerous thyroid nodules on basis of different features like echogenicity, margins, microcalcifications, size, shape and abnormal neck lymph nodes. We therefore aimed to calculate diagnostic accuracy of ultrasound in detection of carcinoma in thyroid nodules taking fine needle aspiration cytology as the reference standard. Materials and Methods: A cross-sectional analytical study was designed to prospectively collect data from December 2010 till December 2012 from the Department of Radiology in Aga Khan University Hospital, Karachi, Pakistan. A total of 100 patients of both genders were enrolled after informed consent via applying non-probability consecutive sampling technique. Patients referred to Radiology department of Aga Khan University to perform thyroid ultrasound followed by fine-needle aspiration cytology of thyroid nodules were included. They were excluded if proven for thyroid malignancy or if their US or FNAC was conducted outside our institution. Results: The subjects comprised 76 (76%) females and 24 males. Mean age was $41.8{\pm}SD$ 12.3 years. Sensitivity and specificity with 95%CI of ultrasound in differentiating malignant thyroid nodule from benign thyroid nodule calculated to be 91.7% (95%CI, 0.72-0.98) and 78.94% (0.68-0.87) respectively. Reported positive predictive value and negative PV were 57.9% (0.41-0.73) and 96.8% (0.88-0.99) and overall accuracy was 82%. Likelihood ratio (LR) positive was computed to be 4.3 and LR negative was 0.1. Conclusions: Ultrasonography has a high diagnostic accuracy in detecting malignancy in thyroid nodules on the basis of features like echogenicity, margins, micro calcifications and shape.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.650-652
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• 2013

As VANET(Vehicular Ad-hoc NETwork) improves road safety, efficiency, and comfort, and provides a value-added service such as commerce information or internet access. it is the most important technology in ITS(Intelligent Transportation System). But, In VANETs, better communication efficiency can be achieved by sacrificing security and vice versa. VANETs cannot get started without either of them. Therefore, to solve these problems simultaneously, this paper proposes MAC(Message Authentication Code) based SDAP(Secure Data Aggregation Protocol) which removes redundant data or abnormal data between vehicles and verifies the integrity of message. The MAC based SDAP not only improves the efficiency of data delivery but also enhances the security by detecting malicious attacks such as propagation jamming attack, forgery attack, and disguised attack.