• Korean Journal of Radiology
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• v.23 no.5
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• pp.505-516
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• 2022

Objective: To evaluate whether artificial intelligence (AI) for detecting breast cancer on mammography can improve the performance and time efficiency of radiologists reading mammograms. Materials and Methods: A commercial deep learning-based software for mammography was validated using external data collected from 200 patients, 100 each with and without breast cancer (40 with benign lesions and 60 without lesions) from one hospital. Ten readers, including five breast specialist radiologists (BSRs) and five general radiologists (GRs), assessed all mammography images using a seven-point scale to rate the likelihood of malignancy in two sessions, with and without the aid of the AI-based software, and the reading time was automatically recorded using a web-based reporting system. Two reading sessions were conducted with a two-month washout period in between. Differences in the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, and reading time between reading with and without AI were analyzed, accounting for data clustering by readers when indicated. Results: The AUROC of the AI alone, BSR (average across five readers), and GR (average across five readers) groups was 0.915 (95% confidence interval, 0.876-0.954), 0.813 (0.756-0.870), and 0.684 (0.616-0.752), respectively. With AI assistance, the AUROC significantly increased to 0.884 (0.840-0.928) and 0.833 (0.779-0.887) in the BSR and GR groups, respectively (p = 0.007 and p < 0.001, respectively). Sensitivity was improved by AI assistance in both groups (74.6% vs. 88.6% in BSR, p < 0.001; 52.1% vs. 79.4% in GR, p < 0.001), but the specificity did not differ significantly (66.6% vs. 66.4% in BSR, p = 0.238; 70.8% vs. 70.0% in GR, p = 0.689). The average reading time pooled across readers was significantly decreased by AI assistance for BSRs (82.73 vs. 73.04 seconds, p < 0.001) but increased in GRs (35.44 vs. 42.52 seconds, p < 0.001). Conclusion: AI-based software improved the performance of radiologists regardless of their experience and affected the reading time.

• Journal of Platform Technology
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• v.12 no.1
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• pp.55-66
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• 2024

The K-POP market has become influential not only in culture but also in society as a whole, including diplomacy and environmental movements. As a result, various papers have been conducted based on machine learning to identify the success factors of idols by utilizing traditional data such as music and recordings. However, there is a limitation that previous studies have not reflected the influence of new media platforms such as Instagram releases, YouTube shorts, TikTok, Twitter, etc. on the popularity of idols. Therefore, it is difficult to clarify the causal relationship of recent idol success factors because the existing studies do not consider the daily changing media trends. To solve these problems, this paper proposes a data collection system and analysis methodology for idol-related data. By developing a container-based real-time data collection automation system that reflects the specificity of idol data, we secure the stability and scalability of idol data collection and compare and analyze the clusters of successful idols through a K-Means clustering-based outlier detection model. As a result, we were able to identify commonalities among successful idols such as gender, time of success after album release, and association with new media. Through this, it is expected that we can finally plan optimal comeback promotions for each idol, album type, and comeback period to improve the chances of idol success.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.21-30
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• 2014

Lately, new influentials have secured a large number of volunteers on social networks due to vitalization of various social media. There has been considerable research on these influential people in social networks but the research has limitations on location information of Location Based Social Network Service(LBSNS). Therefore, the purpose of this study is to propose a spatial detection methodology and application plan for influentials who make comments about diverse social and cultural issues in LBSNS using spatial statistical analysis methods. Twitter was used to collect analysis object data and 168,040 Twitter messages were collected in Seoul over a month-long period. In addition, 'politics,' 'economy,' and 'IT' were set as categories and hot issue keywords as given categories. Therefore, it was possible to come up with an exposure index for searching influentials in respect to hot issue keywords, and exposure index by administrative units of Seoul was calculated through a spatial joint operation. Moreover, an influential index that considers the spatial dependence of the exposure index was drawn to extract information on the influential areas at the top 5% of the influential index and analyze the spatial distribution characteristics and spatial correlation. The experimental results demonstrated that spatial correlation coefficient was relatively high at more than 0.3 in same categories, and correlation coefficient between politics category and economy category was also more than 0.3. On the other hand, correlation coefficient between politics category and IT category was very low at 0.18, and between economy category and IT category was also very weak at 0.15. This study has a significance for materialization of influentials from spatial information perspective, and can be usefully utilized in the field of gCRM in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.63-75
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• 2016

Aquaculture has historically delivered marine products because the country is surrounded by ocean on three sides. Surveys on production have been conducted recently to systematically manage aquaculture facilities. Based on survey results, pricing controls on marine products has been implemented to stabilize local fishery resources and to ensure minimum income for fishermen. Such surveys on aquaculture facilities depend on manual digitization of aerial photographs each year. These surveys that incorporate manual digitization using high-resolution aerial photographs can accurately evaluate aquaculture with the knowledge of experts, who are aware of each aquaculture facility's characteristics and deployment of those facilities. However, using aerial photographs has monetary and time limitations for monitoring aquaculture resources with different life cycles, and also requires a number of experts. Therefore, in this study, we investigated an automatic prototype system for detecting boundary information and monitoring aquaculture facilities based on satellite images. KOMPSAT-3 (13 Scene), a local high-resolution satellite provided the satellite imagery collected between October and April, a time period in which many aquaculture facilities were operating. The ANN classification method was used for automatic detecting such as cage, longline and buoy type. Furthermore, shape files were generated using a digitizing image processing method that incorporates polygon generation techniques. In this study, our newly developed prototype method detected aquaculture facilities at a rate of 93%. The suggested method overcomes the limits of existing monitoring method using aerial photographs, but also assists experts in detecting aquaculture facilities. Aquaculture facility detection systems must be developed in the future through application of image processing techniques and classification of aquaculture facilities. Such systems will assist in related decision-making through aquaculture facility monitoring.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.45-51
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• 2003

This study was conducted to investigate the effects of castration and ovariectomy on growth performance and plasma hormone concentration in pigs. A total of 48 pigs of 35 days of age were used. The results obtained in the present study are summarized as follows: 1. No significant difference was found in average daily gain between ovariectomy group (898.6g) and control gilt group (862.7g), and between castration group (926.0g) and control boar group (945.5g), respectively. Average daily gain of control boar group, however, was significantly higher than that of control gilt group (p<0.05). There was no significant difference in feed/gain between ovariectomy and control gilt group and between castration and control boar group, respectively. Backfat thickness was significantly (p<0.05) higher in ovariectomy or castration group than in control gilt or boar group, respectively. 2. Plasma concentration of IGF-I was significantly (p<0.05) increased during the period of 5 weeks of age (45.1 $\pm$0.72 ng/ml) to 15 weeks of age (356.3$\pm$3.05 ng/ml), and maintained constantly afterwards in control gilt group, as was in control boar group. That of ICF-I tended to be lower in ovariectomy or castration group than in control gilt or boar group, respectively. Regarding steroid hormones of estradiol-17$\beta$, progesterone, and testosterone, the concentration was extremely low at 5 weeks of age, however, increased from 11 weeks to 23 weeks of age in control gilt or boar group, while it was nearly under detection limit in ovariectomy or castration group. 3. Chemical compositions of pork loins were not affected by ovariectomy or castration, except that crude ash content was significantly (p<0.05) higher in castration group than in control boar group. These results indicated that ovariectomy or castration had no effects on growth performance and feed utilization. However, the concentration of sex steroid hormones was under detection limit in ovariectomy and castration group. Further studies, however, are needed to develope the techniques which minimize the stress related with castration or ovariectomy for the production of high quality pork.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.163-171
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• 1980

Recently, Bacillus has been identified as one of food poisoning bacteria especially in products of cereal foods in foreign countries. Therefore, the quantitative distribution of Bacillus cereus in market foods, its physiological characteristics, growth rate by temperature and heat resistance of its spore were examined. Thirty two samples of cooked rice, 20 samples of kimbab(cooked rice rolled with laver), 23 samples of rice cake, 13 samples of rice ana 13 samples of barley were collected from restaurents and food stores in Busan, Korea during the period from May to November in 1980. Forty samples of 101 samples submitted to the test appeared positive for Bacillus cereus showing abut $40\%$ in detection ratio. Detection ratio of Bacillus cereus was higher than $50\%$ in barley and rice, and about $30\%$ in rice products. Average Bacillus cereus content of in the samples was $2.6\times10^6/g$ in cooked rice, $2.3\times10^6/g$in kimbab, $4.9\times10^4/g$ in rice cake while that in rice and barley was about $10^3/g$. The result of biochemical tests of the bacterium was $100\%$ positive in catalase, egg yolk reaction, gelatin hydrolysis and glucose fermentation, $100\%$ negative in xylose, arabinose and mannitol oxidation, about $90\%$ positive in acetoin production, $80.0\%$ positive in nitrate reduction and citrate utilization and $55.0\%$ positive in starch hydrolysis test. Isolation ratio of Bacillus ceresus which showed haemolysis positive and starch hydrolysis negative results, was about $38\%$ in 40 strains examined. It is known that those strains has a close relation to food poisoning accident. Growth rate and generation time of Bacillus cereus isolated from the cooked rice were $0.34hr^{-1},\;2.02hr\;at\;20^{\circ}C,\;0.73hr^{-1},\;0.95hr\;at\;30^{\circ}C\;and\;0.49hr^{-1},\;1.44\;hr\;at\;40^{\circ}C$ respectively. Heat resistance value of Bacillus cereus spores suspended in phosphate buffer solution was $D_{90}=29.0min,\;D_{95}=8.7min,\;D_{98}=3.7\;min\;and\;D_{101}=2.3\;min(z=10.5)$.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2E
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• pp.30-45
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• 2001

This study considers the environmental factors affecting propagation loss and sonar performance in the continental regions of the East Coast Sea of Korea. Water mass distributions appear to change dramatically in a few weeks. Simple calculation with the case when the NKCW (North Korean Cold Water) develops shows that the difference in propagation loss may reach in the worst up to 10dB over range 5km. Another factor, an eddy, has typical dimensions of 100-200km in diameter and 150-200m in thickness. Employing a typical eddy and assuming frequency to be 100Hz, its effects on propagation loss appear to make lower the normal formation of convergence zones with which sonars are possible to detect long-range targets. The change of convergence zones may result in 10dB difference in received signals in a given depth. Thermal fronts also appear to be critical restrictions to operating sonars in shallow waters. Assuming frequency to be 200Hz, thermal fronts can make 10dB difference in propagation loss between with and without them over range 20km. An observation made in one site in the East Coast Sea of Korea reveals that internal waves may appear in near-inertial period and their spectra may exist in periods 2-17min. A simulation employing simple internal wave packets gives that they break convergence zones on the bottom, causing the performance degradation of FOM as much as 4dB in frequency 1kHz. An acoustic experiment, using fixed source and receiver at the same site, shows that the received signals fluctuate tremendously with time reaching up to 6.5dB in frequencies 1kHz or less. Ambient noises give negative effects directly on sonar performance. Measurements at some sites in the East Coast Sea of Korea suggest that the noise levels greatly fluctuate with time, for example noon and early morning, mainly due to ship traffics. The average difference in a day may reach 10dB in frequency 200Hz. Another experiment using an array of hydrophones gives that the spectrum levels of ambient noises are highly directional, their difference being as large as 10dB with vertical or horizontal angles. This fact strongly implies that we should obtain in-situ information of noise levels to estimate reasonable sonar performance. As one of non-stationary noise sources, an eel may give serious problems to sonar operation on or under the sea bottoms. Observed eel noises in a pier of water depth 14m appear to have duration time of about 0.4 seconds and frequency ranges of 0.2-2.8kHz. The 'song'of an eel increases ambient noise levels to average 2.16dB in the frequencies concerned, being large enough to degrade detection performance of the sonars on or below sediments. An experiment using hydrophones in water and sediment gives that sensitivity drops of 3-4dB are expected for the hydrophones laid in sediment at frequencies of 0.5-1.5kHz. The SNR difference between in water and in sediment, however, shows large fluctuations rather than stable patterns with the source-receiver ranges.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.52-60
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• 2003

Objectives: Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. The lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, utilization of simultaneous EEG and EOG processing and analyses to detect stage 1 sleep automatically were attempted. Methods: Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. A relative power of alpha waves less than 50% or relative power of theta waves more than 23% was regarded as stage 1 sleep. SEM(slow eye movement) was defined as the duration of both-eye movement ranging from 1.5 to 4 seconds, and was also regarded as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results were compared to the manual rating results done by two polysomnography experts. Results: A total of 169 epochs were analyzed. The agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3% and Cohen’s Kappa was 0.586 (p<0.01). A significant portion (32%) of automatically detected stage 1 sleep included SEM. Conclusion: Generally, digitally-scored sleep staging shows accuracy up to 70%. Considering potential difficulty in stage 1 sleep scoring, accuracy of 79.3% in this study seems to be strong enough. Simultaneous analysis of EOG differentiates this study from previous ones which mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnari remains a valid one in this study.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.312-321
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• 2003

In this paper, we implement robot which are ability to recognize obstacles and moving automatically to destination. we present two results in this paper; hardware implementation of image processing board and software implementation of visual feedback algorithm for a self-controlled robot. In the first part, the mobile robot depends on commands from a control board which is doing image processing part. We have studied the self controlled mobile robot system equipped with a CCD camera for a long time. This robot system consists of a image processing board implemented with DSPs, a stepping motor, a CCD camera. We will propose an algorithm in which commands are delivered for the robot to move in the planned path. The distance that the robot is supposed to move is calculated on the basis of the absolute coordinate and the coordinate of the target spot. And the image signal acquired by the CCD camera mounted on the robot is captured at every sampling time in order for the robot to automatically avoid the obstacle and finally to reach the destination. The image processing board consists of DSP (TMS320VC33), ADV611, SAA7111, ADV7l76A, CPLD(EPM7256ATC144), and SRAM memories. In the second part, the visual feedback control has two types of vision algorithms: obstacle avoidance and path planning. The first algorithm is cell, part of the image divided by blob analysis. We will do image preprocessing to improve the input image. This image preprocessing consists of filtering, edge detection, NOR converting, and threshold-ing. This major image processing includes labeling, segmentation, and pixel density calculation. In the second algorithm, after an image frame went through preprocessing (edge detection, converting, thresholding), the histogram is measured vertically (the y-axis direction). Then, the binary histogram of the image shows waveforms with only black and white variations. Here we use the fact that since obstacles appear as sectional diagrams as if they were walls, there is no variation in the histogram. The intensities of the line histogram are measured as vertically at intervals of 20 pixels. So, we can find uniform and nonuniform regions of the waveforms and define the period of uniform waveforms as an obstacle region. We can see that the algorithm is very useful for the robot to move avoiding obstacles.

• Journal of agricultural medicine and community health
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• v.28 no.2
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• pp.155-169
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• 2003

Objectives: The purpose of this study is to provide data for the improvement of hypertension management of community health practitioner posts through the study on hypertension management in community health practitioner posts. Methods: A questionnaire was mailed to 700 community health practitioners and 205 of them responded during the period from March 13, 2003 to May 13. The survey results were analyzed using SPSS program, version 11. Results: The results are as follows; 1. There are two major activities in a hypertension prevention project for community: health education and early detection. About 57% of community health care practitioners perform a health education for community people four times a year. The 64.5% of them used the materials for health education provided from a community health center and 22.1% of them performed a post-evaluation. The main method of early detection of hypertension was measurement of blood pressure of person to visit, which was 96.1%. Other methods included home visiting(89.3%), a referral from community hospitals and other resources(49.1%), health promotion events(39.5%), and a review of medical records(35.7%). 2. For the registration and management of patients with hypertension, about 36% of community health centers used a special form and more than 50% of them have registered patients who were managed by other health care institutions in the community. A computerized program was used for the management of patients with hypertension in 68.5% of them. More than 60% of them responded that it was used for report, treatment, and follow-up of patients with hypertension.