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Improving target recognition of active sonar multi-layer processor through deep learning of a small amounts of imbalanced data (소수 불균형 데이터의 심층학습을 통한 능동소나 다층처리기의 표적 인식성 개선)

  • Young-Woo Ryu;Jeong-Goo Kim
    • The Journal of the Acoustical Society of Korea
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    • v.43 no.2
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    • pp.225-233
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    • 2024
  • Active sonar transmits sound waves to detect covertly maneuvering underwater objects and detects the signals reflected back from the target. However, in addition to the target's echo, the active sonar's received signal is mixed with seafloor, sea surface reverberation, biological noise, and other noise, making target recognition difficult. Conventional techniques for detecting signals above a threshold not only cause false detections or miss targets depending on the set threshold, but also have the problem of having to set an appropriate threshold for various underwater environments. To overcome this, research has been conducted on automatic calculation of threshold values through techniques such as Constant False Alarm Rate (CFAR) and application of advanced tracking filters and association techniques, but there are limitations in environments where a significant number of detections occur. As deep learning technology has recently developed, efforts have been made to apply it in the field of underwater target detection, but it is very difficult to acquire active sonar data for discriminator learning, so not only is the data rare, but there are only a very small number of targets and a relatively large number of non-targets. There are difficulties due to the imbalance of data. In this paper, the image of the energy distribution of the detection signal is used, and a classifier is learned in a way that takes into account the imbalance of the data to distinguish between targets and non-targets and added to the existing technique. Through the proposed technique, target misclassification was minimized and non-targets were eliminated, making target recognition easier for active sonar operators. And the effectiveness of the proposed technique was verified through sea experiment data obtained in the East Sea.

Computer Vision Approach for Phenotypic Characterization of Horticultural Crops (컴퓨터 비전을 활용한 토마토, 파프리카, 멜론 및 오이 작물의 표현형 특성화)

  • Seungri Yoon;Minju Shin;Jin Hyun Kim;Ho Jeong Jeong;Junyoung Park;Tae In Ahn
    • Journal of Bio-Environment Control
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    • v.33 no.1
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    • pp.63-70
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    • 2024
  • This study explored computer vision methods using the OpenCV open-source library to characterize the phenotypes of various horticultural crops. In the case of tomatoes, image color was examined to assess ripeness, while support vector machine (SVM) and histogram of oriented gradients (HOG) methods effectively identified ripe tomatoes. For sweet pepper, we visualized the color distribution and used the Gaussian mixture model for clustering to analyze its post-harvest color characteristics. For the quality assessment of netted melons, the LAB (lightness, a, b) color space, binary images, and depth mapping were used to measure the net patterns of the melon. In addition, a combination of depth and color data proved successful in identifying flowers of different sizes and distances in cucumber greenhouses. This study highlights the effectiveness of these computer vision strategies in monitoring the growth and development, ripening, and quality assessment of fruits and vegetables. For broader applications in agriculture, future researchers and developers should enhance these techniques with plant physiological indicators to promote their adoption in both research and practical agricultural settings.

Accuracy of interocclusal record established by different occlusal scans (교합스캔의 이용 방식에 따른 교합면간기록의 정확성)

  • Minjee Kang;Cheong-Hee Lee;Kyu-Bok Lee;So-Yeun Kim;Du-Hyeong Lee
    • Journal of Dental Rehabilitation and Applied Science
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    • v.40 no.3
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    • pp.142-148
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    • 2024
  • Purpose: The purpose of this study was to investigate the accuracy of digital mounting with occlusal scans in the interocclusal record for a full-mouth fixed prosthetic treatment condition. Materials and Methods: The entire maxillary teeth were prepared in a dentiform model and attached to an articulator in maximum intercuspation. Temporary crowns were fabricated and occlusion was adjusted. After scanning the arch with tooth preparation, digital mounting was performed using an occlusion scan of the anterior or posterior teeth areas. The accuracy of the positioned jaw relation was evaluated three-dimensionally through positional deviation and angular error of the occlusal plane. Afterwards, the same procedure was repeated on the partially edentulous model to evaluate the accuracy of digital interocclusal record. Kruskal-Wallis test and Mann-Whitney U test were used for statistical analysis, and the significance level was set at 0.05. Results: There was no significant difference in the positional error at the center of the arch in the digitally established jaw relation depending on the scan area used and remaining tooth conditions (P = 0.53). The angular error of the occlusal plane was larger when the anterior teeth were used as the overlapping area, and a smaller error value was observed when both posterior teeth were used as the overlapping area (P < 0.001). Conclusion: The use of bilateral posterior occlusal scans is recommended when digitally mounting the jaw relation established with temporary teeth during full-mouth fixed prosthetic treatment.

Study on the Measurement of Entrance Surface Dose to the Thyroid and Both Eyes in Dental Panoramic Radiography (치과 파노라마촬영에서의 갑상선과 양쪽 눈의 표면 선량 측정에 대한 연구)

  • Jung-Hoon Lee
    • Journal of the Korean Society of Radiology
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    • v.18 no.6
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    • pp.733-740
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    • 2024
  • Panoramic radiography is a technique that captures high-resolution images of the oral and dental areas of a patient, providing comprehensive information about the patient's entire dental condition in a single image. While panoramic radiography uses much less radiation compared to cone-beam CT (CBCT), the issue of patient radiation exposure cannot be overlooked. This study aimed to measure the entrance surface dose of radiation-sensitive tissues, such as the thyroid and eyes, during panoramic radiography, and to calculate the equivalent dose and effective dose from the measured absorbed dose to compare and analyze it with the dose limits. The experiment was conducted using the Rayscan α-OCL (Ray Co., Ltd. Gyeonggi-do, Korea) dental panoramic X-ray system. The phantom used was a head and neck phantom (Model PH-47, Kyoto Kagaku, Japan), which has an attenuation coefficient similar to that of human tissue. During panoramic radiography, the entrance surface dose was measured for radiation-sensitive tissues like the thyroid and lens. The entrance surface dose measured were 31.36 µGy for the thyroid, 25.70 µGy for the left lens, and 25.13 µGy for the right lens, respectively. To verify the differences in radiation doses for each site, a one-way ANOVA was performed, and a significant difference between groups was confirmed. A post-hoc test classified the left and right lenses into the same group, while the thyroid was classified into a different group. From the measured entrance surface dose, the equivalent doses for the left and right lenses were calculated to be 27.50 µSv and 27.13 µSv, respectively. The equivalent dose and effective dose for the thyroid were 31.36 µSv and 1.2544 µSv, respectively.

Effect of Noise on Density Differences of Tissue in Computed Tomography (컴퓨터 단층촬영의 조직간 밀도차이에 대한 노이즈 영향)

  • Yang, Won Seok;Son, Jung Min;Chon, Kwon Su
    • Journal of the Korean Society of Radiology
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    • v.12 no.3
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    • pp.403-407
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    • 2018
  • Currently, the highest cancer death rate in Korea is lung cancer, which is a typical cancer that is difficult to detect early. Low-dose chest CT is being used for early detection, which has a greater lung cancer diagnosis rate of about three times than regular chest x-ray images. However, low-dose chest CT not only significantly reduces image resolution but also has a weak signal and is sensitive to noise. Also, air filled lungs are low-density organs and the presence of noise can significantly affect early diagnosis of cancer. This study used Visual C++ to set a circle inside a large circle with a density of 2.0, with a density of 1.0, which is the density of water, in which five small circle of mathematics have different densities. Gaussian noise was generated by 1%, 2%, 3%, and 4% respectively to determine the effect of noise on the mean value, the standard deviation value, and the relative noise ratio(SNR). In areas where the density difference between the large and small circles was greatest in the event of 1 % noise, the SNR in the area with the greatest variation in noise was 4.669, and in areas with the lowest density difference, the SNR was 1.183. In addition, the SNR values can be seen to be high if the same results are obtained for both positive and negative densities. Quality was also clearly visible when the density difference was large, and if the noise level was increased, the SNR was reduced to significantly affect the noise. Low-density organs or organs in areas of similar density to cancers, will have significant noise effects, and the effects of density differences on the probability of noise will affect diagnosis.

The Roles of Shop Owners in Boosting Conventional Markets (상권활성화에 있어서 상업자의 역할에 관한 연구)

  • Park, Seung-Je
    • Journal of Distribution Science
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    • v.9 no.4
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    • pp.93-102
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    • 2011
  • With the increasing interest in boosting conventional markets, many authors have paid considerable attention to the roles of shop owners, store image improvement, and how to attract or maintain customers. Nevertheless, it is not easy to find papers related to the relationship between shop owners and their contribution to trading areas, directly or indirectly, in the academic world. Accordingly, research for answering the following question has been initiated: what kind of roles do shopkeepers should play in revitalizing poor conventional markets? Based on the previous studies focusing on enhancing traditional markets, this research was approached from the new insights that have been obtained concerning how to boost conventional markets, that is, from the perspectives of a shop owner and a trader. Therefore, this research aims at identifying some resolutions associated with the roles of shop owners to enhance a shopping district in a specific area, classifying their business roles into a few categories, depending on the degree of their participation in improving the shopping environment. Compared with previous studies focusing on emphasizing the importance of improving customer services from a shopkeeper's perspective, this research provides a new insight as far as how to boost conventional markets. It is, furthermore, necessary to note how market participants, particularly shop owners as they are the key players, can contribute to rebuilding their business area together with their customers. As a research technique for effectively achieving the research goal, the authors adopted a documentation methodology based on a large amount of the existing literature for studying how to rebuild traditional markets. Concerned about the ways to revitalize conventional markets, many authors have proposed a variety of strategies, and have suggested more detailed action plans from a practitioner's perspective. By analyzing these research results, the authors will have accomplished the research aim. Rather than simply identifying the roles of shop owners, the author found that they had to understand their social contribution for enhancing their trading areas, as well as their functional roles, in forming a regional society. The conventional market should be, thus, regarded as the place to share regional culture. Consequently, the authors draw some conclusions from the research results. In order to answer the above question, it was found that the roles of shop owners have been considered as one of the most important ways for revitalizing traditional markets. With respect to their roles, it is evident that their business activities are closely related to the improvement of the trading area in terms of sociality, regional development, and market revitalization, by selling products or services to the customers visiting that area. In a word, this implies that shop owners have to actively take part in boosting conventional markets as a core player. Although the authors have properly achieved the research aim, this study has a limitation, like most other research, in adopting a documentation method. Because the research is based on existing data results provided by the prior research conducted a long time ago, whether the research findings are applicable in a contemporary market should be re-examined in future research from a practitioner's perspective, rather than from an academic's perspective.

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Integrated Study on the Factors Influencing Sustainable Innovation Cluster of Pangyo Techno Valley (판교테크노벨리의 지속가능한 혁신 클러스터 영향요인에 관한 통합연구)

  • Park, Jeong Sun;Park, Sang Hyeok;Hong, Sung Sin
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.1
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    • pp.71-94
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    • 2020
  • Korea's innovation cluster policy has been implemented since 2005 with the goal of balanced regional development. The purpose of this study is to investigate the factors affecting the sustainability of innovative cluster tenants by using Pangyo Techno Valley as an example. Pangyo Techno Valley was established under the leadership of the local government (Gyeonggi-do) rather than the central government and it is called "Silicon Valley of Korea" and "Asia Silicon Valley" and is becoming more representative. The growing number of companies in Pangyo Techno Valley decreased in 2017 compared to 2016. This is because Pangyo Techno Valley's business ecosystem will change from 2019. In this paper, quantitative and qualitative studies were conducted to investigate the influencing factors. Quantitative research was conducted based on the survey and qualitative research was applied through interviews. The quantitative research examined the factors affecting the sustainability of Pangyo Techno Valley, and the qualitative research examined the specific reasons and additional factors for the quantitative research results. The quantitative results showed that factors affecting sustainability in terms of changes in corporate internal conditions, human and physical infrastructure, cooperation and synergy, and occupancy patterns. The specific reason for the impact appeared in the qualitative research process. The support category of local governments did not show any significant factors in quantitative research. In addition, qualitative research suggested 'Good image of Pangyo Techno Valley' as the category that has the greatest impact on sustainability. It is shown that companies are passive and expect the role of local governments in activating cooperation network in Pangyo Techno Valley. In this paper, based on the results of the study, Pangyo Techno Valley is presented with a realistic plan based on real estate issues and an ideal plan with a long-term perspective.

A Study on the Awareness of Dental Patients about Dental Hygienists (치과내원환자의 치과위생사에 대한 인식도 조사 연구)

  • Park, Sung-Suk;Choo, Pyung-Ku
    • Journal of dental hygiene science
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    • v.10 no.3
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    • pp.191-197
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    • 2010
  • The purpose of this study was to examine the awareness of dental patients using dental institutions about dental hygienists in an effort to help educate dental hygiene students to have the right image of dental hygienists. And it's also meant to provide education for dental hygienists to develop their own capabilities, attitude and values to render quality medical services to patients. The subjects in this study were the patients who visited dental clinics and hospitals to receive treatment. A self- administered survey was conducted from March 5 to April 13, 2010, in consideration of their general characteristics. The answer sheets from 204 respondents were gathered, and 197 answer sheets were analyzed except seven incomplete ones. A factor analysis was carried out to find out their general characteristics, and independent-samples t-test and one-way ANOVA were utilized to get statistical data on mean and standard deviation. A SPSS 12.0 program was employed to analyze all the collected data. And it's found that the largest number of the patients thought that the main duty of dental hygienists was to give treatment to patients, and they took a favorable view of their services. They weren't well aware of the process of nurturing dental hygienists and their curriculum, and they put a relatively strong confidence in their treatment and had relatively favorable experiences with them.

Measurements of Carotid Intima, Media, and Intima-media Thickness and Their Clinical Importance (경동맥의 내막, 중막, 내중막 두께 분리측정 및 임상적 중요성)

  • Kim Wuon-Shik;Jeong Hwan-Taek;No Ki-Yong;Bae Jang-Ho
    • Progress in Medical Physics
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    • v.16 no.4
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    • pp.207-213
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    • 2005
  • The severity of carotid Intima-media thickness (IMT) is an Independent predictor of atherosclerosis which causes transient cerebral ischemia, stroke, and coronary events such as myocardial Infarction. The IMT consists of Intima thickness (IT) and media thickness (MT). However, the Individual clinical significance of IT and MT has not been well studied. We devised a method of measuring IT, MT, and IMT using B-mode ultrasound Image processing technique for the diagnosis of atherosclerosis. To inspect the clinical significance of IT, MT, and IMT, one hundred forty-four consecutive patients (mean age; 57 years old, 72 males) were underwent common carotid artery scanning using high-resolution ultrasound. Results showed that, the IT (p<0.05), MT (p<0.05) as well as IMT (p<0.01) of patients with atherosclerotic disease were significantly thicker than that of the patients without atherosclerotic disease. Patients with hyperiension showed significantly thicker IT (p<0.01), MT (p<0.001), and IMT (p<0.001). However, only IT was thicker in patients with smoking (p<0.01). The IT (r=0.374, p=0.001), MT (r=0.433, p=0.000), and IMT (r=0.479, p=0.000) showed positive correlation with age. The coefficients of determination ($r^2$) were estimated to be $92.4\%$ for IMT and MT, $49.1\%$ for IMT and IT, and $27.4\%$ for IT and MT. This result suggests that the Intima layer of the carotid artery has a different physiology with the media layer.

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R-lambda Model based Rate Control for GOP Parallel Coding in A Real-Time HEVC Software Encoder (HEVC 실시간 소프트웨어 인코더에서 GOP 병렬 부호화를 지원하는 R-lambda 모델 기반의 율 제어 방법)

  • Kim, Dae-Eun;Chang, Yongjun;Kim, Munchurl;Lim, Woong;Kim, Hui Yong;Seok, Jin Wook
    • Journal of Broadcast Engineering
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    • v.22 no.2
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    • pp.193-206
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    • 2017
  • In this paper, we propose a rate control method based on the $R-{\lambda}$ model that supports a parallel encoding structure in GOP levels or IDR period levels for 4K UHD input video in real-time. For this, a slice-level bit allocation method is proposed for parallel encoding instead of sequential encoding. When a rate control algorithm is applied in the GOP level or IDR period level parallelism, the information of how many bits are consumed cannot be shared among the frames belonging to a same frame level except the lowest frame level of the hierarchical B structure. Therefore, it is impossible to manage the bit budget with the existing bit allocation method. In order to solve this problem, we improve the bit allocation procedure of the conventional ones that allocate target bits sequentially according to the encoding order. That is, the proposed bit allocation strategy is to assign the target bits in GOPs first, then to distribute the assigned target bits from the lowest depth level to the highest depth level of the HEVC hierarchical B structure within each GOP. In addition, we proposed a processing method that is used to improve subjective image qualities by allocating the bits according to the coding complexities of the frames. Experimental results show that the proposed bit allocation method works well for frame-level parallel HEVC software encoders and it is confirmed that the performance of our rate controller can be improved with a more elaborate bit allocation strategy by using the preprocessing results.