• ETRI Journal
• /
• v.32 no.3
• /
• pp.380-389
• /
• 2010

This paper presents a new edge-protection algorithm and its very large scale integration (VLSI) architecture for block artifact reduction. Unlike previous approaches using block classification, our algorithm utilizes pixel classification to categorize each pixel into one of two classes, namely smooth region and edge region, which are described by the edge-protection maps. Based on these maps, a two-step adaptive filter which includes offset filtering and edge-preserving filtering is used to remove block artifacts. A pipelined VLSI architecture of the proposed deblocking algorithm for HD video processing is also presented in this paper. A memory-reduced architecture for a block buffer is used to optimize memory usage. The architecture of the proposed deblocking filter is verified on FPGA Cyclone II and implemented using the ANAM 0.25 ${\mu}m$ CMOS cell library. Our experimental results show that our proposed algorithm effectively reduces block artifacts while preserving the details. The PSNR performance of our algorithm using pixel classification is better than that of previous algorithms using block classification.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.2
• /
• pp.158-165
• /
• 2018

Recently there is a great interest in the bi-static sonar. However, since the transmitter and the receiver operate on different platforms, it may be necessary to operate the system in a non-cooperative mode. In this situation, the detection and localization performance are limited. Therefore, it is necessary to classify the received pulse from the transmitter to overcome the performance limitation. In this paper, we proposed a robust automatic pulse classification method that can be applied to real systems. The proposed method eliminates the effects of noise and multipath propagation through post-processing and improves the pulse classification performance. We also verified the proposed method through the sea experimental data.

• The Journal of the Acoustical Society of Korea
• /
• v.30 no.8
• /
• pp.461-467
• /
• 2011

Accurate classification of input signals is the key prerequisite for variable bit-rate coding, which has been introduced in order to effectively utilize limited communication bandwidth. Especially, recent surge of multimedia services elevate the importance of speech/music classification. Among many speech/music classifier, the ones based on support vector machine (SVM) have a strong selling point, high classification accuracy, but their computational complexity and memory requirement hinder their way into actual implementations. Therefore, techniques that reduce the computational complexity and the memory requirement is inevitable, particularly for embedded systems. We first analyze implementation of an SVM-based classifier on embedded systems in terms of execution time and energy consumption, and then propose two techniques that alleviate the implementation requirements: One is a technique that removes support vectors that have insignificant contribution to the final classification, and the other is to skip processing some of input signals by virtue of strong correlations in speech/music frames. These are post-processing techniques that can work with any other optimization techniques applied during the training phase of SVM. With experiments, we validate the proposed algorithms from the perspectives of classification accuracy, execution time, and energy consumption.

• Journal of Gastric Cancer
• /
• v.11 no.3
• /
• pp.173-179
• /
• 2011

Purpose: It is difficult to obtain biopsies from gastrointestinal stromal tumors (GISTs) prior to surgery because GISTs are submucoal tumors, despite being the most common nonepithelial neoplasms of the gastrointestinal tract. Unlike anatomic imaging techniques, PET-CT, which is a molecular imaging tool, can be a useful technique for assessing tumor activity and predicting the malignant potential of certain tumors. Thus, we aimed to evaluate the usefulness of PET-CT as a pre-operative prognostic factor for GISTs by analyzing the correlation between the existing post-operative prognostic factors and the maximum SUV uptake (SUVmax) of pre-operative 18F-fluoro-2-deoxyglucose (FDG) PET-CT. Materials and Methods: The study was conducted on 26 patients who were diagnosed with gastric GISTs and underwent surgery after being examined with pre-operative FDG PET-CT. An analysis of the correlation bewteen (i) NIH risk classification and the Ki-67 proliferation index, which are post-operative prognostic factors, and (ii) the SUVmax of PET-CT, which is a pre-operative prognostic factor, was performed. Results: There were significant correlations between (i) SUVmax and (ii) Ki-67 index, tumor size, mitotic count, and NIH risk group (r=0.854, 0.888, 0.791, and 0.756, respectively). The optimal cut-off value for SUVmax was 3.94 between "low-risk malignancy" and "high-risk malignancy" groups. The sensitivity and specificity of SUVmax for predicting the risk of malignancy were 85.7% and 94.7%, respectively. Conclusions: The SUVmax of PET-CT is associated with Ki-67 index, tumor size, mitotic count, and NIH classification. Therefore, it is believed that PET-CT is a relatively safe, non-invasive diagnostic tool for assessing malignant potential pre-operatively.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.4
• /
• pp.195-201
• /
• 2015

For median filtering (MF) detection in altered digital images, this paper presents a new feature vector that is formed from autoregressive (AR) coefficients via an AR model of the gradients between the neighboring row and column lines in an image. Subsequently, the defined 10-D feature vector is trained in a support vector machine (SVM) for MF detection among forged images. The MF classification is compared to the median filter residual (MFR) scheme that had the same 10-D feature vector. In the experiment, three kinds of test items are area under receiver operating characteristic (ROC) curve (AUC), classification ratio, and minimal average decision error. The performance is excellent for unaltered (ORI) or once-altered images, such as $3{\times}3$ average filtering (AVE3), QF=90 JPEG (JPG90), 90% down, and 110% up to scale (DN0.9 and Up1.1) images, versus $3{\times}3$ and $5{\times}5$ median filtering (MF3 and MF5, respectively) and MF3 and MF5 composite images (MF35). When the forged image was post-altered with AVE3, DN0.9, UP1.1 and JPG70 after MF3, MF5 and MF35, the performance of the proposed scheme is lower than the MFR scheme. In particular, the feature vector in this paper has a superior classification ratio compared to AVE3. However, in the measured performances with unaltered, once-altered and post-altered images versus MF3, MF5 and MF35, the resultant AUC by 'sensitivity' (TP: true positive rate) and '1-specificity' (FN: false negative rate) is achieved closer to 1. Thus, it is confirmed that the grade evaluation of the proposed scheme can be rated as 'Excellent (A)'.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.5
• /
• pp.303-313
• /
• 2021

Recently, quality control of the Liquefied Natural Gas Carrier (LNGC) cargo hold and block-erection interference areas using 3D scanners have been performed, focusing on large shipyards and the international association of classification societies. In this study, as a part of the research on LNGC cargo hold quality management advancement, a study on deep-learning-based scaffolding system 3D point cloud object detection and post-processing were conducted using a LNGC cargo hold 3D point cloud. The scaffolding system point cloud object detection is based on the PointNet deep learning architecture that detects objects using point clouds, achieving 70% prediction accuracy. In addition, the possibility of improving the accuracy of object detection through parameter adjustment is confirmed, and the standard of Intersection over Union (IoU), an index for determining whether the object is the same, is achieved. To avoid the manual post-processing work, the object detection architecture allows automatic task performance and can achieve stable prediction accuracy through supplementation and improvement of learning data. In the future, an improved study will be conducted on not only the flat surface of the LNGC cargo hold but also complex systems such as curved surfaces, and the results are expected to be applicable in process progress automation rate monitoring and ship quality control.

• KIPS Transactions on Software and Data Engineering
• /
• v.12 no.8
• /
• pp.333-340
• /
• 2023

Efficient prediction of corporate bankruptcy is an important part of making appropriate lending decisions for financial institutions and reducing loan default rates. In many studies, classification models using artificial intelligence technology have been used. In the financial industry, even if the performance of the new predictive models is excellent, it should be accompanied by an intuitive explanation of the basis on which the result was determined. Recently, the US, EU, and South Korea have commonly presented the right to request explanations of algorithms, so transparency in the use of AI in the financial sector must be secured. In this paper, an artificial intelligence-based interpretable classification prediction model was proposed using corporate bankruptcy data that was open to the outside world. First, data preprocessing, 5-fold cross-validation, etc. were performed, and classification performance was compared through optimization of 10 supervised learning classification models such as logistic regression, SVM, XGBoost, and LightGBM. As a result, LightGBM was confirmed as the best performance model, and SHAP, an explainable artificial intelligence technique, was applied to provide a post-explanation of the bankruptcy prediction process.

• Korean Journal of Clinical Pharmacy
• /
• v.28 no.1
• /
• pp.57-64
• /
• 2018

Background: Patients experience significant differences in aspects of mortality, quality of life, and costs between during the year of receiving liver transplant (LT) and the subsequent years (post-LT). This study aimed to estimate the medical utilization and cost of LT for patients compared to post-LT patients by using a recent National Patient Sample (NPS) data provided by the Korean Health Insurance Review and Assessment Service (HIRA). Methods: This study used a subset of the 2015 HIRA-NPS. Patient claims data that included Z944 (Korean Standard Classification of Diseases code for LT status) were selected. Within the selected data, LT patients were identified based on whether the national health insurance number code of Q80 (procedure code for LT surgery) was included, and they were compared to post-LT patients. Results: In the analysis, 330 patients were included. The average cost per patient was $90,066{\pm}36,959$ thousand KRW and $10,557{\pm}9,668$ thousand KRW for LT and post-LT patients, respectively. Especially, LT patients' costs for injection/procedure, surgery/treatment, and examination were higher than other costs, being $35,983{\pm}18,115$ thousand KRW, $28,246{\pm}9,408$ thousand KRW, and $12,131{\pm}6,604$ thousand KRW, respectively. For inpatients, the average number of hospitalized days was $63.5{\pm}66.0$ days for LT patients and $22.3{\pm}35.1$ days for post-LT patients. Conclusion: Compared to post-LT patients, LT patients had higher costs, especially for injection/procedure, surgery/treatment, and examination. Additionally, the LT group had longer hospitalization duration and higher costs for their hospital admission, whereas they did not show a significant difference in number of visits and medical costs for outpatient-care.

• Journal of Korean Foot and Ankle Society
• /
• v.17 no.1
• /
• pp.28-33
• /
• 2013

Purpose: In previous study, the frequency of osteoarthritis and discomfort were high in ankle fracture-dislocation but detail results about ankle fracture-dislocation has rarely been investigated. In this study, we retrospectively analyze the outcome of the operative treatment of ankle fracture with dislocation for over-2 years follow up. Materials and Methods: There were 47 cases of ankle fracture-dislocation in our hospital from March 2007 to May 2010. We investigated 20 patients who underwent operation and were possible for over-2 years follow up. The result was estimated with the direction of dislocation, fracture type, the time of bone union and post-traumatic osteoarthritis with plain radiologic images. In clinical assessment, we statistically evaluated the function and pain through AOFAS score and Olerud & Molander scoring system. Results: By Lauge-Hansen classification, there were 13 cases(65%) of pronation-external rotation and 6 cases(30%) of supination-external rotation, 1 case(5%) of supination-adduction. AOFAS score was 85.5, and Olerud & Molander score was "excellent" in 8 cases, "good" in 5 cases, "fair" in 3 cases and "poor" in 4 cases. Postoperative complications in 4 cases revealed post-traumatic arthritis. All kinds of lateral dislocation of ankle fracture was 15 cases and the most common. Of these, all 3 cases, anterolateral dislocation showed post-traumatic osteoarthritis. Conclusion: In ankle fracture-dislocation, post-traumatic osteoarthritis occurred in 4 of 20 patient(20%). Especially, the possibility of post-traumatic osteoarthritis was more in cases of anterolateral or lateral dislocation. So, it must be needed that deliberate examination, for example, preoperative MRI and sufficient explanation to patient. Also, we have to follow up the patients carefully.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.21 no.6
• /
• pp.565-574
• /
• 2021

Background: Trigeminal neuralgia (TN) is a severe form of pain that affects the daily activities of a patient. Transcutaneous electrical nerve stimulation (TENS) therapy is an emerging option for the treatment of acute and chronic pain. The aim of this study was to evaluate the effect of TENS therapy as an adjunct to drug therapy for the treatment of TN. Methods: A total of 52 patients diagnosed with TN according to the International Classification of Headache Disorders (version 3) were included. Each patient was randomized to either the TENS or placebo TENS groups. Intervention was given in continuous mode and 100-Hz frequency for 20 mins biweekly for 6 weeks. Parameters were measured at baseline, TENS completion and 3 months, 6 months, and 1 year of follow up. The parameters observed were mean carbamazepine dose, mean visual analog scale (VAS) score, mean present pain intensity (PPI) score, and functional outcome. Non-parametric analyses, one-way ANOVA and the Kruskal-Wallis test were applied for intragroup comparisons, while the Mann-Whitney U test and independent t-test were used for intergroup comparisons of variables. The chi-square test was applied to analyze categorical data. Results: Compared to the placebo TENS group, the mean dose of carbamazepine in the TENS group was significantly reduced at TENS completion, as well as at 6 months and 1 year follow up. Changes in mean VAS score, mean PPI score, and functional outcome did not show significant differences between the groups (P>0.05). Conclusion: TENS therapy does not lead to any changes in pain levels but it may reduce the mean dose of carbamazepine when used as an adjunct treatment in patients with TN.