• 대한산업공학회지
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• 제29권1호
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• pp.90-99
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• 2003

Object clustering, which makes classification for a set of objects into a number of groups such that objects included in a group have similar characteristic and objects in different groups have dissimilar characteristic each other, has been exploited in diverse area such as information retrieval, data mining, group technology, etc. In this study, an object-clustering problem with similarity coefficients between objects is considered. At first, an evaluation function for the optimization problem is defined. Then, a genetic algorithm and local optimization technique based on heuristic method are proposed and used in order to obtain near optimal solutions. Solutions from the genetic algorithm are improved by local optimization techniques based on object relocation and cluster merging. Throughout extensive experiments, the validity and effectiveness of the proposed algorithms are tested.

• Structural Engineering and Mechanics
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• 제73권4호
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• pp.437-445
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• 2020

The microstructure and mechanical properties of concrete will degrade significantly at high temperatures, thus affecting the bond strength between reinforcing steel and surrounding concrete in reinforced concrete members. In this study, the effect of individual and hybrid fiber on the local bond-slip behavior of lightweight aggregate concrete (LWAC) after exposure to elevated temperatures was experimentally investigated. Tests were conducted on local pullout specimens (150 mm cubes) with a reinforcing bar embedded in the center section. The embedment lengths of the pullout specimens were 4.2 times the bar diameter. The parameters investigated included concrete type (control group: ordinary LWAC; experimental group: fiber reinforced LWAC), concrete strength, fiber type, and targeted temperature. The test results showed that for medium-strength LWACs exposed to high temperatures, the use of only steel fibers did not significantly increase the residual bond strength. Moreover, the addition of individual and hybrid fiber had little effect on the residual bond strength of the high-strength LWAC after exposure to a temperature of 800℃.

• Bulletin of the Korean Chemical Society
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• 제18권6호
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• pp.573-578
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• 1997

Ion fragmentations of fatty acids such as stearic acid, palmitic acid, myristic acid, and lauric acid were studied using mass spectrometry and semiempirical calculations. The mass spectra of fatty acids showed the distributions of CH₃(CH₂)$_n^+$ and $[(CH_2)_nCO_2H]^+$ fragment ions. The relative ion abundance distributions of $[(CH_2)_nCO_2H]^+$ showed the local maxima at n=6, 10, and 14. The local maximum phenomena were also found in the mass spectra of methyl stearate but not in those of normal alcohols. These local maxima could be explained not by heats of reaction for fragmentation but by the cyclic structures of the molecular ions. The AM1 semiempirical calculations for fatty acids clearly show that the linear structures are more favorable than the cyclic ones for neutral molecules while the cyclic structures are more favorable than the linear ones for ionic molecules. The distances between carboxyl group and methylene of the cylic structures of ionized fatty acids were calculated. The methylene carbons with n=6, 10, and 14 were closer to the carboxyl group than adjacent ones.

• ETRI Journal
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• 제43권4호
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• pp.580-593
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• 2021

When operating in confined spaces or near obstacles, collision-free path planning is an essential requirement for autonomous exploration in unknown environments. This study presents an autonomous exploration technique using a carefully designed collision-free local planner. Using LiDAR range measurements, a local end-point selection method is designed, and the path is generated from the current position to the selected end-point. The generated path showed the consistent collision-free path in real-time by adopting the Euclidean signed distance field-based grid-search method. The results consistently demonstrated the safety and reliability of the proposed path-planning method. Real-world experiments are conducted in three different mines, demonstrating successful autonomous exploration flights in environment with various structural conditions. The results showed the high capability of the proposed flight autonomy framework for lightweight aerial robot systems. In addition, our drone performed an autonomous mission in the tunnel circuit competition (Phase 1) of the DARPA Subterranean Challenge.

• Radiation Oncology Journal
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• 제35권1호
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• pp.71-77
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• 2017

Purpose: Although the technical developments of radiotherapy have been remarkable, there are currently few reports on the treatment results of radiotherapy for local recurrence of rectal cancer treated with surgery alone as initial treatment in this three-dimensional conformal radiotherapy era. Thus, we retrospectively evaluated the treatment results of radiotherapy for local recurrence of rectal cancer treated with surgery alone as the initial treatment. Materials and Methods: Thirty-two patients who underwent radiotherapy were enrolled in this study. The dose per fraction was 2.0-3.5 Gy. Because the treatment schedule was variable, the biological effective dose (BED) was calculated. Results: Local control (LC) and overall survival (OS) rates from the completion of radiotherapy were calculated. The 1-, 2-, 3-, 4-, and 5-year LC rates were 51.5%, 24.5%, 19.6%, 19.6%, and 13.1%, respectively. LC rates were significantly higher for the high BED group (${\geq}75Gy_{10}$) than for the lower BED group (<$75Gy_{10}$). All patients who reported pain achieved pain relief. The duration of pain relief was significantly higher for the high BED group than for the lower BED group. The 1-, 2-, 3-, 4-, and 5-year OS rates were 82.6%, 56.5%, 45.2%, 38.7%, and 23.2%, respectively. There was a trend toward higher OS rates in with higher BED group compared to lower BED group. Conclusion: For patients with unresectable locally recurrent rectal cancer treated with surgery alone, radiotherapy is effective treatment. The prescribed BED should be more than $75Gy_{10}$, if the dose to the organ at risk is within acceptable levels.

• 대한간호학회지
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• 제29권1호
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• pp.97-106
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• 1999

This study was designed to investigate the effect of a hand massage program on anxiety and immune function in patients during cataract surgery. The hand massage program, in this study, consisted of hand massage and hand-holding. The subjects were sixty-three patients, thirty for the experimental and thirty-three for the control group, who were admitted at Kang Nam St. Mary's Hospital for cataract surgery. This study was carried out from December 10, 1997 to February 26, 1998. The level of anxiety as measured by the Visual Analogue Scale, systolic blood pressure, diastolic blood pressure, and pulse rate were measured before, after hand massage, and after hand-holding. Epinephrine, norepinephrine, cortisol, blood sugar levels, neutrophil, lymphocyte, and natural killer cell percentages also were measured before hand massage and five minutes before the end of the operation. Data were analyzed by t-tests, ANCOVA, repeated measures ANOVA, and Bonferroni multiple comparisons. The results were as follows : 1) After hand massage, psychological anxiety levels decreased significantly compared with before hand massage in the experimental group, not in the control group. After hand holding, there were significant decrease in both groups. 2) There were not significant differences on systolic blood pressure, diastolic blood pressure, and pulse rates in both groups. 3) The hand massage program decreased epinephrine, norepinephrine, and cortisol significantly in the experimental group, and increased epinephrine, norepinephrine, and cortisol in the control group. 4) There were no differences in blood sugar levels, neutrophil and lymphocyte percentages in white blood cells after the hand massage program. However, natural killer cells in lymphocytes were significantly increased in the experimental group. These findings indicate that a hand massage program could be a effective nursing intervention in decreasing the psychological and physiological anxiety levels and improving immune function in clients having cataract surgery under local anesthesia.

• Journal of Dental Anesthesia and Pain Medicine
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• 제19권5호
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• pp.277-288
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• 2019

Background: This study evaluated the efficacy of virtual reality (VR) distraction and counter-stimulation (CS) on dental anxiety and pain perception to local anesthesia in children. Methods: A prospective, randomized, single-blinded interventional clinical trial with a parallel design was used. Seventy children 7-11 years old who required local anesthesia (LA) for pulp therapy or tooth extraction were recruited and allocated to two groups with equal distribution based on the intervention. Group CS (n = 35) received CS and Group VR (n = 35) received VR distraction with ANTVR glasses. Anxiety levels (using pulse rate) were evaluated before, during, and after administration of local anesthesia, while pain perception was assessed immediately after the injection. Wong-Baker faces pain-rating scale (WBFPS), visual analog scale (VAS), and Venham's clinical anxiety rating scale (VCARS) were used for pain evaluation. Student's t-test was used to test the mean difference between groups, and repeated measures ANOVA was used to test the mean difference of pulse rates. Results: Significant differences in mean pulse rates were observed in both groups, while children in the VR group had a higher reduction (P < 0.05), and the mean VCARS scores were significant in the VR group (P < 0.05). Mean WBFPS scores showed less pain perception to LA needle prick in the CS group while the same change was observed in the VR group with VAS scores. Conclusions: VR distraction is better than CS for reducing anxiety to injection in children undergoing extraction and pulpectomy.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권6호
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• pp.347-355
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• 2023

Background: Eye movement desensitization and reprocessing (EMDR) therapy has been reported to be very efficacious for treating post-traumatic stress disorder (PTSD) and other anxiety-related conditions. However, a review of the literature reveals the sparse use of this therapy in the field of pediatric dentistry. This study aimed to evaluate anxiety trends in pediatric dental patients during local anesthesia and extraction with and without EMDR therapy. Methods: Children in the age range of 8-12 years who required dental extractions were assigned randomly into two groups: an EMDR group (group 1) and a routine behavior management therapy group (group 2; receiving more traditional interventions such as tender love and care behavioral modeling, and distraction). Anxiety scores were recorded at four levels using the visual facial anxiety scale (VFAS) preoperatively, after therapy, after the administration of local anesthesia (LA), and after extraction. Results: Reduced anxiety was observed after the delivery of EMDR therapy, after LA administration, and post-extraction in the EMDR group compared to pre-operative anxiety scores of anxiety (P < 0.001; unpaired Student's t and Mann-Whitney U tests). In the control group, mild reductions in anxiety after routine behavior management therapy were observed, accompanied by spikes in anxiety levels after LA and extractions. Conclusion: EMDR therapy was found to be valuable for reducing anxiety among pediatric dental patients during tooth extraction procedures.

• Journal of Dental Anesthesia and Pain Medicine
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• 제24권2호
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• pp.119-128
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• 2024

Background: In pediatric dentistry, fear and anxiety are common among children. Local anesthetics (LA) are widely used to control pain and reduce discomfort in children during dental treatment. Topical anesthetics play a vital role in reducing pain and the unpleasant sensation of a needle puncture in children. Peppermint oil has been extensively used for various diseases. However, its anesthetic properties remain unknown. Peppermint oil, used in mouthwashes, toothpastes, and other topical preparations has analgesic, anesthetic, and antiseptic properties. This study aimed to compare and evaluate pain perception following the topical application of peppermint oil versus lignocaine spray before an intraoral injection in children, aged 8-13 years. Method: Fifty-two children, aged between 8-13 years, who required local anesthesia for dental treatment were divided into two groups of 26 each by simple random sampling (Group 1: 0.2% peppermint oil and Group 2: lignocaine spray). In both groups, physiological measurements (e.g., heart rate) were recorded using pulse oximetry before, during, and after the procedure. Objective pain measurement (Sound Eye Motor (SEM) scale) during administration and subjective measuremeant (Wong-Baker Faces Pain Rating Scale (WBFPRS)) after LA administration were recorded. This was followed by the required treatment of the child. Physiological parameters were compared between the two groups using an independent t-test for intergroup assessment and a paired t-test and repeated-measures ANOVA for intragroup comparisons. The Mann-Whitney U test was used to analyze the pain scores. Results: Intragroup mean heart rates, before, during, and after treatment were statistically significantly different (P < 0.05). However, the intergroup mean pulse rates did not differ significantly between the two groups. The mean WBFPS score in the lignocaine spray group was 4.133 ± 2.06 was statistically different from that of the peppermint oil group (0.933 ± 1.03; P < 0.001^*). The mean SEM score was significantly lower in the peppermint oil group than that in the lignocaine spray group (P = 0.006). No negative effects were observed in this study. Conclusion: 0.2% peppermint oil was effective in reducing pain perception.

• 농촌계획
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• 제26권2호
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• pp.13-24
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• 2020

This study analyzed the management efficiency of local food stores that are increasing recently. The analysis targeted 25 local food outlets in Jeonbuk area, and the analysis method analyzed the efficiency by CCR model. The input variables used to analyze the input-oriented efficiency of local food stores are business expenses, employees, organizational number of participating farms, and number of items, and sales are used as output variables. The main contents of the analysis are as follows. First, local food outlets increased due to support projects such as the government, local governments, and agricultural cooperatives, but their dependence was high. Second, the management efficiency of 25 local food stores in Jeonbuk is 28.0% when the efficiency is 1.000, and 72.0% of inefficient local food stores. Third, considering the projection point and the reference group, there was room for improvement in input variables. Therefore, it was determined that improvement efforts are needed to secure the continuity of local food outlets in the future. However, this study will require review of variable selection and analysis methods for further analysis.