• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.6
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• pp.659-665
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• 2019

Various placards are attached to the surface of a container depending on the risk of the cargo loaded. Containers with dangerous goods should be managed separately from ordinary containers. Therefore, as part of the port automation system, there is a demand for automatic recognition of placards. In this paper, proposed is a system that automatically extracts the placard area based on the shape features of the placard and recognizes the contents in it. Various distortions can be caused by the surface curvature of the container, therefore, attention should be paid to the area extraction and recognition process. The proposed system can automatically extract the region of interest and recognize the placard using the feature that the placard is diamond shaped and the class number is written just above the lower vertex. When the proposed system is applied to real images, the placard can be recognized without error, and the used techniques can be applied to various image analysis systems.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.57-64
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• 2021

The domestic semiconductor industry can produce various products that will satisfy customer needs by diversifying assembly parts and increasing compatibility between them. It is necessary to improve the production line as a method to reduce the work-in-process inventory (WIP) in the assembly line, the idle time of the worker, and the idle time of the process. The improvement of the production line is to balance the capabilities of each process as a whole, and to determine the timing of product input or the order of the work process so that the time required between each process is balanced. The purpose of this study is to find the optimal WIP and buffer size through SA (Simulated Annealing) that minimizes lead time while matching the number of two parts in a parallel assembly line with bottleneck process. The WIP level and buffer size obtained by the SA algorithm were applied to the CONWIP and DBR systems, which are the existing production systems, and the simulation was performed by applying them to the new hybrid production system. Here, the Hybrid method is a combination of CONWIP and DBR methods, and it is a production system created by setting new rules. As a result of the Simulation, the result values were derived based on three criteria: lead time, production volume, and work-in-process inventory. Finally, the effect of the hybrid production method was verified through comparative analysis of the result values.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.116-122
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• 2020

Human and material resource planning is one representative example of Operations Research. Resource planning is important not only in civilian settings but also in military ones. In the Air Force, flight scheduling is one of the primary issues that must be addressed by the personnel who are connected to flight missions. However, although the topic is of great importance, relatively few studies have attempted to resolve the problem on a scientific basis. Each flight squadron has its own scheduling officers who manually draw up the flight schedules each day. While mistakes may not occur while drafting schedules, officers may experience difficulties in systematically adjusting to them. To increase efficiency in this context, this study proposes a mathematical model based on a binary variable. This model automatically drafts flight schedules considering pilot's mission efficiency. Furthermore, it also recommends that schedules be drawn up monthly and updated weekly, rather than being drafted from scratch each day. This will enable easier control when taking the various relevant factors into account. The model incorporates several parameters, such as matching of the main pilots and co-pilots, turn around time, availability of pilots and aircraft, monthly requirements of each flight mission, and maximum/minimum number of sorties that would be flown per week. The optimal solution to this model demonstrated an average improvement of nearly 47% compared with other feasible solutions.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.431-441
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• 2020

Purpose: Various studies have indicated that reduced-port robotic gastrectomies are safe and feasible for treating patients with early gastric cancer. However, there have not been any comparative studies conducted that have evaluated patients with clinically advanced gastric cancer. Therefore, we aimed to compare the perioperative outcomes of D2 lymph node dissections during reduced-port robotic distal subtotal gastrectomies (RRDGs) and conventional 5-port laparoscopic distal subtotal gastrectomies (CLDGs). Materials and Methods: We retrospectively evaluated 118 patients with clinically advanced gastric cancer who underwent minimally invasive distal subtotal gastrectomies with D2 lymph node dissections between February 2016 and November 2019. To evaluate the patient data, we performed a 1:1 propensity score matching (PSM) according to age, sex, body mass index, American Society of Anesthesiologists physical status classification score, and clinical T status. The short-term surgical outcomes were also compared between the two groups. Results: The PSM identified 40 pairs of patients who underwent RRDG or CLDG. The RRDG group experienced a significantly longer operation time than the CLDG group (P<0.001), although the RRDG group had significantly less estimated blood loss (P=0.034). The number of retrieved extraperigastric lymph nodes in the RRDG group was significantly higher than that of the CLDG group (P=0.008). The rate of postoperative complications was not significantly different between the two groups (P=0.115). Conclusions: D2 lymph node dissections can be safely performed during RRDGs and the perioperative outcomes appear to be comparable to those of conventional laparoscopic surgeries. Further studies are needed to compare long-term survival outcomes.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.187-193
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• 2021

Purpose: This study aimed to assess the usefulness of machine learning and automation techniques to match pairs of panoramic radiographs for personal identification. Materials and Methods: Two hundred panoramic radiographs from 100 patients (50 males and 50 females) were randomly selected from a private radiological service database. Initially, 14 linear and angular measurements of the radiographs were made by an expert. Eight ratio indices derived from the original measurements were applied to a statistical algorithm to match radiographs from the same patients, simulating a semi-automated personal identification process. Subsequently, measurements were automatically generated using a deep neural network for image recognition, simulating a fully automated personal identification process. Results: Approximately 85% of the radiographs were correctly matched by the automated personal identification process. In a limited number of cases, the image recognition algorithm identified 2 potential matches for the same individual. No statistically significant differences were found between measurements performed by the expert on panoramic radiographs from the same patients. Conclusion: Personal identification might be performed with the aid of image recognition algorithms and machine learning techniques. This approach will likely facilitate the complex task of personal identification by performing an initial screening of radiographs and matching ante-mortem and post-mortem images from the same individuals.

• Health Policy and Management
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• v.31 no.1
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• pp.46-55
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• 2021

Background: Patients with the chronic physical illness are more likely to experience depression, and the accompany of chronic physical illness and depression is particularly high in middle-aged and elderly women. Considering that depression is associated with somatization and the decline of therapeutic compliance when accompanied by chronic physical illness, middle-aged and elderly women who experience depression among chronic physical illness may increase their use of medical services. This study is to identify the effect of depression on the use of medical services, especially among middle-aged and elderly women with chronic physical illness. Methods: This study used the 2016 Korean Health Panel. For analysis, it used T-test, negative binomial regression, and multivariate regression combining propensity score matching. Results: First, depressive groups had a higher number of medical service utilization and total medical expenditure than the non-depressive group. Second, depression significantly increased medical service utilization (β=0.17, p=0.04) at the 5% significance level. Also, depression significantly increased total medical expenditure (β=0.37, p=0.08) at the 10% significance level. Conclusion: For those who have chronic physical illness among middle-aged and elderly women, the experience of depression was confirmed to be a factor affecting the use of medical services. In the end, it is important to come up with policy countermeasures for middle-aged and elderly women accompanied by depression and chronic physical illness.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.369-379
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• 2021

This study was a descriptive survey study to compare the stress, depression, fatigue, and sleep quality between pregnant women with gestational diabetes mellitus (GDM) and normal pregnant women. The study subjects were 49 gestational diabetes mellitus women and 51 normal pregnant women who were matching with gestational diabetes mellitus women by age, gestational age and number of births. The data collection was measured using structured questionnaires, numerical scales, and Canopy9 RSA(IEMBIO, Gangwondo, Korea) equipment. As a result of the study, pregnant women with gestational diabetes had higher pre-pregnancy weight(t=3.698, p<.001) and higher stress(t=4.505, p<.001), depression(t=4.564, p<.001), and fatigue(t=3.709, p<.001) during pregnancy, so weight management is important before pregnancy, and stress, fatigue, and depression relief nursing

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.17-32
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• 2022

This study explored an approach to estimate a flow-density diagram(FD) on a link in highway traffic environment by utilizing probe vehicles' time headway records. To study empirical flow-density diagram(EFD), the probe vehicles with vision sensors were recruited for collecting driving records for nine months and the vision sensor data pre-processing and GIS-based map matching were implemented. Then, we examined the new EFDs to evaluate validity with reference diagrams which is derived from loop detection traffic data. The probability distributions of time headway and distance headway as well as standard deviation of flow and density were utilized in examination. As a result, it turned out that the main factors for estimation errors are the limited number of probe vehicles and bias of flow status. We finally suggest a method to improve the accuracy of EFD model.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.599-607
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• 2021

Street-view images, which are omnidirectional scenes centered on a specific location on the road, can provide various obstacle information for the pedestrians. Pedestrian network data for the navigation services should reflect the up-to-date obstacle information to ensure the mobility of pedestrians, including people with disabilities. In this study, the object detection model was trained for the bollard as a major obstacle in Seoul using street-view images and a deep learning algorithm. Also, a process for updating information about the presence and number of bollards as obstacle properties for the crosswalk node through spatial matching between the detected bollards and the pedestrian nodes was proposed. The missing crosswalk information can also be updated concurrently by the proposed process. The proposed approach is appropriate for crowdsourcing data as the model trained using the street-view images can be applied to photos taken with a smartphone while walking. Through additional training with various obstacles captured in the street-view images, it is expected to enable efficient information update about obstacles on the road.

• Journal of IKEEE
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• v.26 no.4
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• pp.537-544
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• 2022

This paper analyzes the occurrence and cause of bond wires fusing used in the manufacture of pulsed high power amplifiers. Recently GaN HEMT has been spotlight in the fields of electronic warfare, radar, base station and satellite communication. In order to produce the maximum output power, which is the main performance of the high-power amplifier, optimal impedance matching is required. And the material, diameter and number of bond wires must be determined in consideration of not only the rated current but also the heat generated by the transient current. In particular, it was confirmed that compound semiconductor with a wide energy band gap such as GaN trigger fusing of the bond wire due to an increase in thermal resistance when the design efficiency is low or the heat dissipation is insufficient. This data has been simulated for exothermic conditions, and it is expected to be used as a reference for applications using GaN devices as verified through IR microscope.