• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.483-488
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• 2020

In recent years, the demand for wireless devices incorporating several wireless communication systems into one has been increasing in order to provide services that meet the diverse needs of consumers. Wireless devices consisting of various wireless communication systems require many frequency fixed filters. A frequency tunable filter can replace a number of frequency fixed filters in the wireless devices. If a frequency tunable filter is used in wireless systems, the system can be configured more efficiently. In this paper, a 3-pole frequency tunable BPF(bandpass filter) operating in the frequency band of 800 ~ 2400MHz is designed. In order to widen the operating frequency band, a tuning screw is designed to have a step and a linear motor is used to facilitate the adjustment of the tuning screw. The implemented frequency tunable BPF operates in the designed frequency range and has the maximum insertion loss of 2.82dB in the channel band and the minimum attenuation of 18.7dB at ± 50MHz frequency offset from the center frequency of the band.

• 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.

• International Area Studies Review
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• v.20 no.4
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• pp.37-56
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• 2016

The purpose of this research is to present the implication for Korean firms' entry into the power market in Myanmar. This study investigated the characteristics of the Myanmar power market and analyzed SWOT, focusing on energy policy, power supply and demand, energy relations with neighboring countries and climate change issue. Opportunity factors are changes in energy strategies, the launch of an energy integration organization, changes in the power energy portfolio, rapid economic and power demand growth, and a clean development mechanism. The threats are high nonfulfillment of a contract, high power loss rates and low electricity distribution rates, increased energy exports to neighboring countries, and vulnerability to climate change. We suggest the use of CHP (Combined Heat and Power), Clean Development Mechanism (CDM), and Multilateral Development Bank (MDB).

• Journal of the Korean Society of Safety
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• v.36 no.1
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• pp.44-49
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• 2021

Domestic industrial accidents continue to increase, with 2,142 deaths in 2018, up by 185 (9.5%) from 1,957 deaths in 2017. Industrial accidents that cause loss of human lives pose a serious risk to businesses because of the strengthening of safety regulations and the changing public perception of social responsibility. Accordingly, to prevent industrial accidents, companies regularly conduct onsite safety activities and conduct education and training to raise awareness among employees. However, many such corporate activities are not conducted voluntarily and practically by employees but mostly by formal implementation. To discontinue this customary and passive behavior of employees and establish a mature safety culture, strengthening the execution power of safety management at the site is of paramount importance, and to this end, we aim to utilize the safety practice index (SPI). In this study, the SPI calculated on the basis of the results of the 2018 and 2019 risk management and safety activities of a site was compared with the reported safety accidents. The results confirmed that the SPI index can be used as a valid indicator for safety activities for accident prevention, such as strengthening leadership and safety policies to grade and manage safety management levels for a certain period of time or by a department or to convert weaknesses into strengths.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.4
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• pp.183-194
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• 2020

Recently, the number of hip dysplasia (DDH) that occurs during infant and child growth has been increasing. DDH should be detected and treated as early as possible because it hinders infant growth and causes many other side effects In this study, two modelling techniques were used for multiple training techniques. Based on the results after the first transformation, the training was designed to be possible even with a small amount of data. The vertical flip, rotation, width and height shift functions were used to improve the efficiency of the model. Adam optimization was applied for parameter learning with the learning parameter initially set at 2.0 x 10e-4. Training was stopped when the validation loss was at the minimum. respectively A novel image overlay system using 3D laser scanner and a non-rigid registration method is implemented and its accuracy is evaluated. By using the proposed system, we successfully related the preoperative images with an open organ in the operating room

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.85-96
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• 2021

Irrigation return flow is defined as the excess of irrigation water that is not evapotranspirated by direct surface drainage, and which returns to an aquifer. It is important to quantitatively estimate the irrigation return flow of the water cycle in an agricultural watershed. However, the previous studies on irrigation return flow rates are limitations in quantifying the return flow rate by region. Therefore, simulating irrigation return flow by accounting for various water loss rates derived from agricultural practices is necessary while the hydrologic and hydraulic modeling of cultivated canal-irrigated watersheds. In this study, the irrigation return flow rate of agricultural water, especially for the entire agricultural watershed, was estimated using the SWMM (Storm Water Management Model) module from 2010 to 2019 for the Madun reservoir located in Anseong, Gyeonggi-do. The results of SWMM simulation and water balance analysis estimated irrigation return flow rate. The estimated average annual irrigation return flow ratio during the period from 2010 to 2019 was approximately 55.3% of the annual irrigation amounts of which 35.9% was rapid return flow and 19.4% was delayed return flow. Based on these results, the hydrologic and hydraulic modeling approach can provide a valuable approach for estimating the irrigation return flow under different hydrological and water management conditions.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.224-236
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• 2021

The objective of this study was to investigate the effects of quality grade (QG) on the physicochemical composition and eating quality attributes of pork belly and shoulder butt. Seventy-two growing-finishing crossbred pigs were slaughtered and their carcasses were graded according to the Korean pork carcass grading system. Based on the grading criteria, the carcasses were classified into: QG 1+ (n=23), QG 1 (n=23) and QG 2 (n=26) groups. At 24 h postmortem, belly and shoulder butt cuts were collected from the QG groups and used for analysis of meat quality, flavor compounds and eating quality attributes. Results showed that the variation in fat content among QG was approximately 2% in the both cut types. The QG showed no effects on all the quality traits: cooking loss, pH and color of the belly or shoulder butt (p>0.05). Thirty-five flavor compounds comprising mainly fatty acids oxidation/degradation-derived products (e.g., aldehydes) and only few Maillard reaction-derived products (e.g., sulfur-and nitrogen-containing compounds) were identified. However, the QG showed a minor effect on the flavor profiles in both the belly and shoulder butt. Regarding the sensory quality, no effects of the QG were found on all the eating quality attributes (color, flavor, juiciness, tenderness and acceptability) for both the belly and shoulder butt cuts (p>0.05). Thus, it may be concluded that the current pork carcass grading standards do not reflect the real quality and value of the belly and shoulder butt cuts.

• Journal of Korea Foundry Society
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• v.41 no.1
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• pp.11-15
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• 2021

Scrap steel used as a charge material in melting process of cast iron foundry is mostly press scrap. The press scrap usually causes several problems including energy loss, workability, safety, and so on. By charging the shredded scrap instead of the press scrap, it is expected that the above-mentioned problems can be solved. In this study, the power basic units to produce cast iron by using the press and shredded scrap are compared in 3t/h medium-frequency induction melting furnace. Charging the shredded scrap instead of the press scrap was confirmed that the power basic unit is improved by about 15%. The characteristics and restrictions of the usage according to the shape and size of scrap steel were considered.

• Korean Journal of Head & Neck Oncology
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• v.37 no.2
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• pp.51-55
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• 2021

Background/Objectives: Extracapsular dissection has the advantage of reducing complications by minimizing tissue loss of the parotid without intentionally exposing the facial nerve in patients with benign parotid tumor. However, there has been controversy over the surgical results. Thus, the surgical outcomes of extracapsular dissection for benign parotid tumor was compared to those of superficial parotidectomy. Materials & Methods: A retrospective chart review was conducted with 132 patients who received surgery for benign parotid tumor in our center from January 2014 to December 2018 retrospectively. Results: A total of 132 people were enrolled, with 62 people receiving extracapsular dissection, 38 people receiving partial superficial parotidectomy and 32 people receiving superficial parotidectomy. No significant difference was found between the three groups regarding complications such as facial nerve palsy, Frey's syndrome, or first bite syndrome. Operation time and hospital stay was significantly short in extracapsular dissection group. Conclusion: For well-selected cases, extracapsular dissection can be considered as an option for surgery of benign parotid tumor.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.389-396
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• 2022

Deep Learning is based on a perceptron, and is currently being used in various fields such as image recognition, voice recognition, object detection, and drug development. Accordingly, a variety of learning algorithms have been proposed, and the number of neurons constituting a neural network varies greatly among researchers. This study analyzed the learning characteristics according to the number of neurons of the currently used SGD, momentum methods, AdaGrad, RMSProp, and Adam methods. To this end, a neural network was constructed with one input layer, three hidden layers, and one output layer. ReLU was applied to the activation function, cross entropy error (CEE) was applied to the loss function, and MNIST was used for the experimental dataset. As a result, it was concluded that the number of neurons 100-300, the algorithm Adam, and the number of learning (iteraction) 200 would be the most efficient in deep learning learning. This study will provide implications for the algorithm to be developed and the reference value of the number of neurons given new learning data in the future.