• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.768-776
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• 2021

Current protection-coordination methods use the reverse time characteristics of the T-C curve, which is not effective for a LVDC distribution system because the protective operation time of converters and DC circuit breakers is much faster than AC protection devices. Therefore, an algorithm is proposed for fault-section isolation using the fault current slope to minimize the blackout region and coordinate between converters and protection devices in a rapid and accurate manner. The method deals with the slope characteristics of a fault current, which may depend on the fault location in an LVDC distribution system. Thus, an LVDC distribution system can be operated in a stable manner by isolating the fault section selectively before the shutdown of the main converter using slope characteristics, which change in proportion to the line impedance and fault location. A 1.5-kV LVDC distribution system was modeled to verify the effectiveness of the proposed algorithm using PSCAD/EMTDC. The system is composed of a distribution substation, LVDC converter, and distribution lines. The simulation results confirm that the proposed algorithm is a useful tool for minimizing the fault section in an LVDC distribution system.

• Therapeutic Science for Rehabilitation
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• v.6 no.1
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• pp.45-54
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• 2017

Objective : The purpose of this study was to investigate the effects of an Interactive Metronome on increasing attention and impulsivity control for children with attention deficit hyperactivity disorder(ADHD). Methods : This study was conducted through the ABA'design among single-case research methods with one child with ADHD. From May to July, 2014, 3 sessions of baseline phase(A), 15 sessions of intervention phase(B), and 3 sessions of post baseline(A') were conducted. The intervention was IM training, and each session carried out short form assessment(SFA) of IM and concentration tasks. In addition, long form assessment(LFA) of IM and Self-Control Rating Scale (SCRS) were conducted at baseline, intervention and post baseline. Results : After IM training as the intervention, the participation showed an increase in attention and controled in impulsivity. After the intervention, it was demonstrated that the effects were maintained or improved in the post baseline. Conclusions : IM training can be useful for increasing attention and impulsivity control of children with ADHD. The results demonstrated the efficacy of IM training as a new approach for children with ADHD.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.38-44
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• 2018

Ammonia is used primarily as a refrigerant in refrigeration facility and SCR of a plant, and is frequently involved in leakage accidents. This study was conducted by selecting ammonia, a material with a wide influence range when evaluated, as a material with higher vapor pressure and lighter than air. In this study, the influence ranges were computed using KORA(Korea Off-site Risk Assessment supporting tool) with four different environmental factors : ground roughness, sealing, operating temperature, pressure, and leakage hole size. As a result, the difference in the influence range of ground roughness is approximately 4.62 times, while the ammonia storage tank shows a difference in the reduction rate of 0.64 when sealed. The extent of impact increased with increasing leakage depending on storage temperature and pressure, and when storing higher than the saturation vapor pressure, the impact range showed an average growth rate of 3.45 % per 0.1 Mpa($45^{\circ}C$). The influence ranges based on the size of the leakage holes is shown to be proportional to the area of the leakage zone.

• Korean Journal of Clinical Pharmacy
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• v.16 no.2
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• pp.113-122
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• 2006

Purpose: A retrospective study was performed to assess the efficacy and tolerance of ${\beta}-blocker$ administration in patients with heart failure and diabetes. Method: Records of 164 patients who were treated for the heart failure condition more than a year were studied retrospectively. Patients were divided into 4 groups based on their diabetes(DM) status and the administration of ${\beta}-blockers$ ($DM+{\beta}-blocker$ group: 14, DM w/o ${\beta}-blocker$: 19, No DM + ${\beta}-blocker$: 62, No DM + no ${\beta}-blocker$: 69). All patients had been receiving conventional therapy such as digoxin, ACE-I, ARB, diuretics, nitrates, aspirin, anticoagulants or lipid-lowering agents. The primary endpoints (death and hospital admission) were recorded during 1 year period and hemodynamic factors (HR, LVEF, SBP, DBP) were obtained from all patient groups before and after 12 months of ${\beta}-blocker$ treatment. To evaluate toxicity of ${\beta}-blocker$, SCr, BUN, AST, ALT and Alkaline phosphatase were obtained. Result: There were less death and hospital admission in DM + ${\beta}-blocker$ group than in DM without ${\beta}-blocker$ group (p=0.014). Relative risk of hospital admission for $DM+{\beta}-blocker$ group over no DM group was 1.17. Long term ${\beta}-blocker$ administration was associated with an improvement of heart rate in patients with DM (P< 0.02) with no significant improvement of LVEF, SBP, DBP. in DM patient. In patient without DM, ${\beta}-blocker$ was associated with improvement in LVEF, HR and DBP (P<0.01, P<0.03), but not in SBP. The incidence of toxicity was similar between the four group with no significant difference. Conculsion: Treatment of heart failure patients with ${\beta}-blocker$ appears to be beneficial in terms of hospital admission event and several hemodynamic factors. The toxicities of ${\beta}-blocker$ treatment were not significant and the treatment is generally well-tolerated in most of the heart failure patients.

• Clean Technology
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• v.27 no.1
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• pp.61-68
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• 2021

Selective catalytic reduction (SCR) is widely used as a method of removing nitrogen oxide in large-capacity thermal power generation systems. Uniform mixing of the injected ammonia and the inlet flue gas is very important to the performance of the denitrification reduction process in the catalyst bed. In the present study, a computational analysis technique was applied to the ammonia injection system design process of a denitrification facility. The applied model is the denitrification facility of an 800 MW class coal-fired power plant currently in operation. The flow field to be solved ranges from the inlet of the ammonia injection system to the end of the catalyst bed. The flow was analyzed in the two-dimensional domain assuming incompressible. The steady-state turbulent flow was solved with the commercial software named ANSYS-Fluent. The nozzle arrangement gap and injection flow rate in the ammonia injection system were chosen as the design parameters. A total of four (4) cases were simulated and compared. The root mean square of the NH3/NO molar ratio at the inlet of the catalyst layer was chosen as the optimization parameter and the design of the experiment was used as the base of the optimization algorithm. The case where the nozzle pitch and flow rate were adjusted at the same time was the best in terms of flow uniformity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.652-657
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• 2018

Breeding control in a farm is a very important factor affecting milk productivity. Breeding management is important for the early detection of estrus, and reliable, automatic, more accurate, and faster monitoring of the timing of dairy cows is essential for farmers. This study measured the accuracy of estrus using the estrus indications, changes in activities, rumination activities, ruminal temperature, and pH. The biomedical information device S1 used in this study provided an estrus notice using the rumen temperature, pH, cow activities, and number of drinking estimations, which were inserted in the rumen through the oral route. The S2 device was used in the estrus notice for the rumen activities and cow activities. The data collected on the instrument were collected at intervals of 2 hours per day at the reference days (RD: -7~-3, +7~+ 3) +2), 7 days before insemination, and 7 days after insemination. The activities of the S1 device used in this paper increased with increasing number of insemination days (-1: $12.5{\pm}1.03/day$; 0: $12.9{\pm}1.73/day$) compared to the reference day (RD: $10.2{\pm}1.0/day$). The activities of the S2 device was also found to increase from the reference day to the insemination day (0: $63.0{\pm}3.66$) compared to the reference day (RD: $40.3{\pm}2.68$). The number of daily drinks in S1 decreased from the reference day (RD: $5.9{\pm}0.89/day$) to before the insemination day (-2: $5.6{\pm}0.98$; -1: $5.7{\pm}0.96$); +2: $6.0{\pm}0.73$). The number of daily drinks on the insemination day (0: $6.3{\pm}0.86$; +2: $6.0{\pm}0.73$) was similar to the reference day. The number of daily rumination in S2 decreased from the reference day (RD: $493.8{\pm}10.92$) to the insemination day (-1: $390.2{\pm}13.36$; 0: $354.1{\pm}16.71$).

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.21-38
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• 2020

Currently, in-port emissions are a serious problem in port cities. However, emissions, especially non-greenhouse gases, from the operation of cargo handling equipment (CHE) have received significant attention from scientific circles. This study estimates the amount of emissions from on-land port diesel-powered CHE in the Port of Incheon. With real-time activity data provided by handling equipment operating companies, this research applies an activity-based approach to capture an up-to-date and reliable diesel-powered CHE emissions inventory during 2017. As a result, 105.6 tons of carbon monoxide (CO), 243.2 tons of nitrogen oxide (NOx), 0.005 tons of sulfur oxide (Sox), 22.8 tons of particulate matter (PM), 26.0 tons of volatile organic compounds (VOCs), and 0.2 tons of ammonia (NH3) were released from the landside CHE operation. CO and NOx emissions are the two primary air pollutants from the CHE operation in the Port of Incheon, contributing 87.71% of the total amount of emissions. Cranes, forklifts, tractors, and loaders are the four major sources of pollution in the Port of Incheon, contributing 84.79% of the total in-port CHE emissions. Backward diesel-powered machines equipped in these CHE are identified as a key cause of pollution. Therefore, this estimation emphasizes the significant contribution of diesel CHE to port air pollution and suggests the following green policies should be applied: (1) replacement of old diesel powered CHE by new liquefied natural gas and electric equipment; (2) the use of NOx reduction after-treatment technologies, such as selective catalytic reduction in local ports. In addition, a systematic official national emission inventory preparation method and consecutive annual in-port CHE emission inventories are recommended to compare and evaluate the effectiveness of green policies conducted in the future.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.217-224
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• 2012

In general, transportation sources include both on-road vehicles and off-road equipment. Off-road vehicles have usually used diesel engines, which have the disadvantage of high NOx emission. Common rail direct injection (CRDI) and after-treatment systems have been applied to meet the exhaust gas emission regulations for diesel vehicles. In the present, agricultural machinery has satisfied the Tier 3 emission regulations by using waste gate turbocharger (WGT) and internal exhaust gas recirculation (EGR). In this paper, the combustion and emission characteristics of an EGR system applied to a 56kW off-road vehicle in non-road transient cycle (NRTC) mode have been investigated. The EGR map was made from foundation experiments determining the EGR duty for all engine operating conditions, and then this map was applied to the NRTC mode. Consequently, the NOx emission was reduced by the EGR system, and the Tier 4 interim emission regulations were satisfied by using both the EGR system and an after-treatment system.

• Atmosphere
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• v.25 no.4
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• pp.693-706
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• 2015

A shift of first fowering date (FFD) of spring blossoms (cherry, peach and pear) over the northest Asia under global warming is investiaged using dynamically downscaled daily temperature data with 12.5 km resolution. For the study, we obatained gridded daily data with Historical (1981~2010), and Representative Concentration Pathway (RCP) (2021~2100) 4.5 and 8.5 scenarios which were produced by WRFv3.4 in conjunction with HadGEM2-AO. A change on FFDs in 21st century is estimated by applying daily outputs of WRFv3.4 to DTS phonological model. Prior to projection on future climate, the performances of both WRFv3.4 and DTS models are evaluated using spatial distribution of climatology and SCR diagram (Normalized standard deviation-Pattern correlation coefficient-Root mean square difference). According to the result, WRFv3.4 and DTS models well simulated a feature of the terrain following characteristics and a general pattern of observation with a marigin of $1.4^{\circ}C$ and 5~6 days. The analysis reveals a projected advance in FFDs of cherry, peach and pear over the northeast Asia by 2100 of 15.4 days (9.4 days). 16.9 days (10.4 days) and 15.2 days (9.5 days), respectively, compared to the Historical simulation due to a increasing early spring (Februrary to April) temperature of about $4.9^{\circ}C$ ($2.9^{\circ}C$) under the RCP 8.5 (RCP 4.5) scenarios. This indicates that the current flowering of the cherry, peach and pear over analysis area in middle or end of April is expected to start blooming in early or middle of April, at the end of this century. The present study shows the dynamically downscaled daily data with high-resolution is helpeful in offering various useful information to end-users as well as in understanding regional climate change.

• Korean Journal of Psychosomatic Medicine
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• v.3 no.2
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• pp.139-146
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• 1995

Forty patients meeting DSM-III-H criteria for panic disorder and 51 normal controls were assessed with the Personality Diagnostic Questionnaire-Revised(PDQ-R), a self-rating scale designed to assess Axis II personality disorders and traits. Results replicated previous findings of a preponderance of dependent, avoidant, and histrionic features. But our result showed other features such as paranoid, schizotypal, borderline, and antisocial traits also. Patients were divided into two groups according to the severity of their personality traits(high or low). These groups were compared in various panic symptomatology and SCL-90-R. None of the specific symptom dimensions in panic disorder, i.e. panic, anxiety, agoraphobia, social impairment, or chronicity was different between groups. Rather, high personality trait groups were found to have significantly more symptomatology in SCR-90-R than low personality groups. Result indicated that patients exhibiting a greater number of personality traits were also significantly more symptomatic. The results suggested a possible link beteween panic disorder and personality disorder. And, general factors such as depression, social or interpersonal sensitivity might provide a much better explanation of personality disorders in panic patients.