• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.40-46
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• 2012

Purpose : To investigate the feasibility of in vivo proton magnetic resonance spectroscopy (MRS) for evaluation of lung cancer. Materials and Methods: This prospective study was approved by the institutional review board of our hospital and informed consent was obtained in all patients. Ten patients (7 men, 3 women; mean age, 64.4) with pathologicallyproven lung cancer (mean, 56.8 mm; range, 44-77 mm) were enrolled to 1.5 T MRS using a single-voxel respiration-triggered point-resolved spectroscopic sequence. Technical success rate and the reason of technical failure, if any, were investigated. Results: Out of 10 lung cancers, analyzable MRS spectra were obtained in 8 tumors (technical success rate, 80%). Two MRS datasets were not able to be analyzed due to serious baseline distortion. Choline and lipid signals were detected as major metabolites in analyzable MRS spectra. Conclusion: In vivo proton MRS method using a single-voxel respiration-triggered point-resolved spectroscopic sequence is feasible in obtaining the MR spectra of lung cancer because these spectra were analyzable and high success rate was shown in our study although there was the limitation of small patient group.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.2
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• pp.103-113
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• 2001

This paper described a design and implementation of a single-chip encoder/decoder using the LZSS algorithm and entropy coding in 0.6${\mu}{\textrm}{m}$ CMOS technology. Dictionary storage for the dictionary search processor(DISP) used a 2K$\times$8bit on-chip memory with 50MHz clock speed. It performs compression on byte-oriented input data at a data rate of one byte per clock cycle except when one out of every 33 cycles is used to update the string window of dictionary. In result, the average compression ratio is 46% by applied entropy coding of the LZSS codeword output. This is to improved on the compression performance of 7% much more then LZSS.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1479-1494
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• 2015

Since the Markowitz's mean-variance framework for portfolio analysis, the topic of portfolio optimization has been an important topic in finance. Traditional approaches focus on maximizing the expected return of the portfolio while minimizing its variance, assuming that risky asset returns are normally distributed. The normality assumption however has widely been criticized as actual stock price distributions exhibit much heavier tails as well as asymmetry. To this extent, in this paper we employ the genetic algorithm to find the optimal portfolio under the Value-at-Risk (VaR) constraint, where the tail of risky assets are modeled with the generalized Pareto distribution (GPD), the standard distribution for exceedances in extreme value theory. An empirical study using Korean stock prices shows that the performance of the proposed method is efficient and better than alternative methods.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.480-484
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• 2006

본 논문에서는 코드 영역을 분리하기 위한 전처리 과정 중 코드 추출에 적합한 자동 이진화 알고리즘을 제안하여, 반복과정을 제거하고 정확한 코드영역 추출로 인식률 및 속도를 향상 시켰다. 배경이 복잡한 이미지가 들어 올 경우 기존의 전역 평균 임계값이나 클래스간의 분산을 이용한 방법으로는 이미지 코드 영역을 찾아 낼 수 없었던 문제를 해결하기 위하여 이미지 코드 주변에 배경과 구분을 두기 위한 흰색 영역이 있다는 점을 착안, 상하좌우 방향 바깥쪽에서 안쪽으로 탐색하여 가장 밝은 값을 갖는 값을 찾아내고 찾아낸 그룹 중 가장 낮은 값을 임계값으로 선택하여 최적의 임계값을 찾아 내었고 이를 통해 복잡한 영상 내에서도 이미지 코드 영역을 찾아낼 수 있다. 제안된 이진화 알고리즘의 성능을 평가하기 위하여 2000장의 테스트 이미지에 적용한 결과, 기존의 이진화 알고리즘들 보다 정확성뿐만 아니라 속도 면에서도 우수한 것을 확인하였다.

• Journal of the Korean Chemical Society
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• v.65 no.1
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• pp.25-36
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• 2021

This study aimed to analyze achievement characteristics of Korean students in the results of PISA 2018 science domain. To this end, the characteristics of PISA 2009 to PISA 2018 science were analyzed in terms of the percentage of each performance level and the ratio of male and female by achievement level; in addition, the percentage of correct answers by framework subscale was compared with PISA 2015. The results showed that Korea has a higher percentage of students at the lower level of achievement as compared to the high-ranking countries of PISA, and the ratio of students at the higher level of achievement was lower. On average, the difference in achievement between boys and girls was negligible; however, but at the higher achievement level, the ratio of boys continued to be higher than that of girls. In addition, in the PISA science framework, the percentage of correct answers of the questions corresponding to 'personal' of 'contexts', 'evaluate and design scientific enquiry' of 'competencies', 'epistemic' of 'knowledge', and 'high' of 'cognitive demand' increased; similarly, and achievement improved as compared to PISA 2015. Based on these results of the study, we propose a method for improving teaching and evaluation to foster Korean students' scientific competence.

• Journal of The Korean Association of Information Education
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• v.26 no.5
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• pp.327-340
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• 2022

This study applied effective playful learning to increase the learning motivation of non-CS major students to help them achieve learning and to successfully operate online SW liberal arts classes for 560 students. As a result of analyzing the students' reflection journals, most of the students accepted the 'white radish' of dialect names as fun playful learning in the process of learning local variables and global variables. And they were surprised and amazed at discovering unexpected contents in our SW class. It was found that they experienced delight in learning, learning-flow, confidence, and intrinsic motivation. In the final term exam at the end of the semester, it was confirmed that the correct rate of 92% for questions related to local and global variables was higher than the average rate of other questions' correctness of 67.1%.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.45-53
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• 2005

Nowadays, using the mobile communication devices, such as a mobile phone, PDA, telematics device, and so forth, are increasing. The large parts of the services with these mobile devices are the position tracking and the route planning. For offering these services, it is increasing the use of the spatial data on the mobile environment. Although the storage of mobile device expands more than before, it still lacks the necessary storage on the spatial data. In this paper, lossy compression technique on the spatial data is suggested, and then it is analyzed the compression ratio and the amount of loss data by the test. Suggested compression technique on the spatial data at this paper is applied to the real-data, and others methods, suggested at the previous studies, is applied to same data. According as the results from both are compared and analyzed, compression technique suggested at this study shows better performance when the compression result is demanded the high position accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.472-482
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• 2016

The purpose of this study was to determine if a geriatric injury would have a statistically significant relationship with the spatial safety within a specific region. To achieve the objectives of this study, an independent sample t-test and One-way ANOVA were performed to verify difference in mean value of regional safety grade, depending on the injury intentionality, injury location, activities at the time of injury, and injury mechanism, in 6,572 geriatric injury patients by combining the National Hospital Discharge Patients Injury Survey data and regional safety index data. The results of statistical validation suggested that there was no difference in the mean value of regional safety grade by sub-group with respect to the injury intentionality. However, a statistically significant difference was observed in terms of the mean value of regional safety grade in each sub-group with regard to the injury location, activities at the time of injury, and injury mechanism in connection with some areas of the regional safety index. Based on the results of such analysis, we derived and presented 3 implications related to policies and practice for the prevention of geriatric injury and a reduction of its occurrence rate in light of spatial safety after a discussion of the results through a comparison with previous studies that examined individual areas.

• 한국노년학
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• v.31 no.4
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• pp.985-998
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• 2011

This study was conducted to understand current management status of 'day and night care' facilities and to explore the related factors with rates of operation of them. The nationwide mailing survey was conducted with structured questionnaires from July, 14, 2010 to July, 28, 2010. The subjects were 277 facilities (response rate 24.5%). Regarding the types of operating, 79.1% of faculties was run by cooperation, and 17.8% and 3.6% for individuals and national/public institutes respectively. The average of operation rate was 70.15%. National/public institutes showed higher in the rate of operation(79.08%) than 72.49% of cooperations and 57.78% of individuals. The number of manpower was not nearly different by the types of operating bodies, but the number of nurse was significantly different among them. The national/public institutions had 1.07 nurses while individual institutions have only 0.08. We found that facilities run by national/public institutes and founded before 2008 years showed higher rate of operation. In case of providing regular monitoring and evaluation services, and music program for patients showed higher rate of operation. In addition, the number of managers, social workers, and nurses increase the rate of operation. We suggest that quality management and monitoring program for the facilities which run by individuals or established after 2008 years would be developed. We also call for development of programs for facilitating utilization of 'day and night care' facilities such as expanding the family support.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.1-8
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• 2013

This study focuses on a ship detection and tracking method using Frequency Modulated Continuous Wave (FMCW) radar used for horizontal surveillance. In general, FMCW radar can play an important role in maritime surveillance, because it has many advantages such as low warm-up time, low power consumption, and its all weather performance. In this paper, we introduce an effective method for data and signal processing of ship's detecting and tracking using the X-band radar. Ships information was extracted using an image-based processing method such as the land masking and morphological filtering with a threshold for a cycle data merged from raw data (spoke data). After that, ships was tracked using search-window that is ship's expected rectangle area in the next frame considering expected maximum speed (19 kts) and interval time (5 sec). By using this method, the tracking results for most of the moving object tracking was successful and those results were compared with AIS (Automatic Identification System) for ships position. Therefore, it can be said that the practical application of this detection and tracking method using FMCW radar improve the maritime safety as well as expand the surveillance coverage cost-effectively. Algorithm improvements are required for an enhancement of small ship detection and tracking technique in the future.