• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.23-31
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• 2020

In the construction sector, there were 99 fatalities from falls associated with steel tube and system scaffolds for three years from 2016 to 2018 and out of which 27.3 percent (27 workers) were found to have occurred during installing and dismantling procedure. To erect scaffolding which is installed for the work at height, the work platforms are generally installed first and the safety guardrails are installed and vice versa to dismantle. As a result, workers are exposed to the risk of falling because they erect and dismantle scaffolding without guardrails. To minimize the risk of falling, it is necessary to study a new construction method that can erect or dismantle scaffolding while guardrails are installed (called advanced guardrail system). This study analyzed advanced guardrail system in terms of safety regulation, workability and economic efficiency by investigating the domestic situation on the use of scaffolding, reviewing domestic and foreign standards for guardrails and conducting economic feasibility study. The results of this study is expected to greatly contribute to preventing falls in scaffolding installation and dismantlement procedure. As a follow-up study, empirical research is required including physical test of scaffolding with advanced guardrail system and effectiveness analysis after trial applications.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.114-114
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• 2014

We present our activities linking to planning of possible forms of large program to study on circumstellar H2O and SiO maser sources with KaVA. A great advantage of KaVA for the stellar maser observations is the combination of the unique capability of the multi-frequency phase referencing technique of KVN and the dual-beam astrometry of VERA with the KaVA's relative dense antenna configuration. We have demonstrated this advantage through the test observations conducted by the KaVA Evolved Stars Sub-working Group since 2012 March. Snapshot KaVA imaging is confirmed to be possible in integration time of 0.5 hour at the 22 GHz band and 1.0 hour at the 43 GHz band in typical cases. This implies that large snapshot imaging surveys towards many H2O and SiO stellar masers are possible within a reasonable machine time (e.g., scans on ~100 maser sources within 200 hours). This possibility enables us to select the maser sources, which are suitable for future long-term (10 years) intensive (biweekly-monthly) monitoring observations, from 1000 potential target candidates selected from dual-frequency band (K/Q-bands) KVN single-dish observations. The output of the survey programs will be used for statistical analysis of the structures of individual stellar maser clumps and the spatio-kinematical structures of circumstellar envelopes with accelerating outflows. The combination of astrometry in milliarcsecond(mas) level and the multi-phase referencing technique yields not only trigonometric parallax distances to the masers but also precise position reference for registration of different maser lines. The accuracy of the map registration affects interpretation of the excitation mechanism of the SiO maser lines and the origin of the variety of the maser actions, which are expected to reflect periodic behaviors of the circumstellar envelope with stellar pulsation. Currently we are checking the technical feasibility of KaVA operations for this combination. After this feasibility test, the long-term monitoring campaign program will run as one of KaVA's legacy projects.

• Journal of Gastric Cancer
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• v.14 no.3
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• pp.187-195
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• 2014

Purpose: Laparoscopic gastrectomy in obese patients has been investigated in several studies, but its feasibility has rarely been examined in morbidly obese patients, such as in those with a body mass index (BMI) of ${\geq}30kg/m^2$. The present study aimed to evaluate the technical feasibility and safety of laparoscopic gastrectomy in morbidly obese patients with gastric cancer. Materials and Methods: A total of 1,512 gastric cancer patients who underwent laparoscopic distal gastrectomy (LDG) were divided into three groups: normal (BMI< $25kg/m^2$, n=996), obese (BMI $25{\sim}30kg/m^2$, n=471), and morbidly obese ($BMI{\geq}30kg/m^2$, n=45). Short-term surgical outcomes, including the course of hospitalization and postoperative complications, were compared between the three groups. Results: The morbidly obese group had a significantly longer operating time (240 minutes vs. 204 minutes, P=0.010) than the normal group, but no significant differences were found between the groups with respect to intraoperative blood loss or other complications. In the morbidly obese group, the postoperative morbidity and mortality rates were 13.3% and 0%, respectively, and the mean length of hospital stay was 8.2 days, which were not significantly different from those in the normal group. Subgroup analysis showed that postoperative complication rates were not high in morbidly obese patients, independent of the type of anastomosis technique used and level of lymph node dissection. Conclusions: LDG is technically feasible and safe in morbidly obese patients with a BMI of ${\geq}30kg/m^2$ and early gastric carcinoma. Except for a longer operating time, LDG might represent a reasonable treatment option in these patients.

• Journal of Internet Computing and Services
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• v.21 no.2
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• pp.19-26
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• 2020

This paper analyses the feasibility of using implantable antennas to detect and monitor tumors. We analyze this setting according to the wireless propagation loss and signal fading produced by human bodies and their environment in an indoor scenario. The study is based on the ITU-R propagation recommendations and prediction models for the planning of indoor radio communication systems and radio local area networks in the frequency range of 300 MHz to 100 GHz. We conduct primary estimations on 915 MHz and 2.4 GHz operating frequencies. The path loss presented in most short-range wireless implant devices does not take into account the human body as a channel itself, which causes additional losses to wireless designs. In this paper, we examine the propagation through the human body, including losses taken from bones, muscles, fat, and clothes, which results in a more accurate characterization and estimation of the channel. The results obtained from our simulation indicates a variation of the return loss of the spiral antenna when a tumor is located near the implant. This knowledge can be applied in medical detection, and monitoring of early tumors, by analyzing the electromagnetic field behavior of the implant. The tumor was modeled under CST Microwave Studio, using Wisconsin Diagnosis Breast Cancer Dataset. Features like the radius, texture, perimeter, area, and smoothness of the tumor are included along with their label data to determine whether the external shape has malignant or benign physiognomies. An explanation of the feasibility of the system deployment and technical recommendations to avoid interference is also described.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7627-7632
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• 2015

Background: The present study was conducted to evaluate the technical feasibility, safety and adequacy of surgical margins with salvage transoral robotic surgery (TORS) for recurrent or residual head and neck squamous cell carcinoma patients. Materials and Methods: Thirty patients who underwent salvage TORS using the 'DaVinci' robot were enrolled in the study and data related to their surgical time, complications and functional outcome were recorded. Results: The feasibility of salvage TORS in our study was observed to be 100%. Positive margins were encountered in only 6.7% of patients. Mean blood loss was 23.3 ml with no patient requiring blood transfusion. Postoperative complications in the form of primary haemorrhage requiring active surgical intervention occurred in 13.3%. Oral feeding could be started as early as the 3rd postoperative day in a few patients, with nasogastric tubes being removed on the 12th postoperative day. Long term gastrostomy tube dependency was seen in 10% cases. Median survival of patients was 19 months. Conclusions: Salvage TORS is a safe, effective and feasible option in the management of treatment failure cases. It offers an alternative surgical approach with unexpected benefits in terms of tracheostomy tube use, Ryle's tube and gastrostomy dependence.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.39.4-40
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• 2017

According to the Korean government's Long-term Space Development Plan 2040, "Creative space science research" is included in a statement to investigate the origin and evolution of the universe by conducting a series of Korean space telescope missions: launch of space telescopes on a small satellite and an international collaboration explorer by 2020, a mid-size domestic space telescope by 2030, and a large size Korea leading international space telescope by 2040. We studied the feasibility of the future Korean Space Telescope (KST) for a mid-size domestic satellite platform. In order to pursue the uniqueness of the science program, we consider a wide range of observing wavelength (0.2um ~ 2.0um) with a spectral resolution of R~6 in the NUV and optical bands, and R~30 for NIR, utilizing an off-axis TMS(Three Mirror System) optics with a wide field of view ($2{\times}4$ degrees) which is optimized for ultra-low surface brightness sources. The main science goals of the mission include investigations of the galaxy formation, cosmic web, and the cosmic background radiation in the NUV-NIR regions. In this paper, we present the science cases and several technical challenges to be resolved along with the future milestones for the success of the KST mission.

• ETRI Journal
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• v.42 no.5
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• pp.669-685
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• 2020

5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.232-243
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• 2010

Gas hydrates are crystalline solids composed of water and gas molecules. Water molecules are linked through hydrogen bonding and create cavities(host lattice) that can capture a large variety of guest molecules under appropriate conditions, generally high pressure and low temperature. Recently, many researchers try to apply gas hydrates to industrial processes to capture greenhouse gases due to the facts that the process is eco-friendly and target gas molecules can be preferentially captured. In this paper, we introduced recent studies on $CO_2$ and $CO_2-N_2$ mixture hydrates to evaluate the feasibility of industrial application of gas hydrate technology to $CO_2$ capture process. Specifically, we put emphasis on the technical feasibility of $CO_2$ separation in steel industry using gas hydrate formation principles.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.105-113
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• 2010

Method or work type improvement is needed in relation to reducing cost and increasing efficiency by ensuring construction quality and reducing labor in the form work process. This would have a great influence on the entire construction process, and make the process of adopting materials and methods more rational and economic. Hence, this study aimed to develop a Synthetic Resins Euroform that could improve durability, water-proofing, sophistication, and organizational unity through the use of injection modeling. Accordingly, this paper first investigated various performance requirements and necessary techniques, and then verified feasibility by evaluating the physical safety and technical validity when it is applied to construction field. In addition, this study evaluated the constructability, safety performance, environmental performance, and systemic excellence in terms of maintaining convenience of Synthetic Resins Euroform. Moreover, to verify feasibility in the construction field, this study analyzed and evaluated the maximum stress by measuring the load and deformation of the space of the horizontal furring, which is attached to Euroform as an armature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.413-421
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• 2006

The bubble dynamics induced by direct laser heating is experimentally analyzed as a first step to assess the technical feasibility of laser-based ink-jet technology. To understand the interaction between laser light and ink, the absorption spectrum is measured for various ink colors and concentrations. The hydrodynamics of laser-generated bubbles is examined by the laser-flash photography. When an Ar ion laser pulse (wavelength 488 nm) with an output power up to 600 mW is incident on the ink solution through a transparent window, a hemispherical bubble with a diameter up to ${\sim}100{\mu}m$ can be formed with a lifetime in a few tens of microsecond depending on the laser power and the focal-spot size. Parametric study has been performed to reveal the effect of laser pulse width, output power, ink concentration, and color on the bubble dynamics. The results show that the bubble generated by a laser pulse is largely similar to that produced by a thin-film heater. Consequently, the present work demonstrates the feasibility of developing a laser-actuated droplet generation mechanism for applications in ink-jet print heads. Furthermore, the results of this work indicate that the droplet generation frequency is likely to be further increased by optimizing the process parameters.