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        검색결과 3,105

        1.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Multiple fractures, particularly femoral fractures, are increasingly prevalent and associated with high mortality rates and significant functional impairments. This highlights the urgent need for effective rehabilitation strategies, such as robot-assisted training, to enhance recovery and improve quality of life. Objectives: This study aimed to evaluate the clinical effectiveness of robotassisted rehabilitation for multiple femoral fractures. Design: Single-subject design. Methods: A 15-day A-B-A' single-subject design was employed. A man in his 30s with multiple fractures underwent standard rehabilitation during the baseline (A) and regression baseline (A') phases, with robotic therapy introduced during the intervention phase (B). Daily assessments of mobility and balance were analyzed using the two-standard deviation method. Results: Robotic therapy led to significant improvements: the TUG test time decreased from 16.21±0.64 seconds (A) to 10.63±0.46 seconds (B) and 9.64±0.35 seconds (A'). The 10 MWT time improved from 6.31±0.64 seconds (A) to 5.41±0.17 seconds (B) and 5.01±0.12 seconds (A'). LOS increased from 364.01±35.83 cm² (A) to 484.67±29.97 cm² (B) and 518.03±18.82 cm² (A'). Plantar pressure imbalance (59.2% right, 40.8% left in A) was corrected to nearly equal distribution in B (49.4%/50.6%) and A' (50.8%/49.2%). Conclusion: Robotic rehabilitation therapy improves balance and weightbearing capacity in patients with multiple fractures, suggesting its effectiveness as an early intervention following bone union.
        4,000원
        2.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Chronic ankle instability (CAI) is very common disease. Strength exercise, balance exercise, and proprioceptive exercise were used to improvement of function for CAI. Isokinetic strength and balance are related to functional movement of lower extremity. Objectives: The purpose was to analyze the effect of muscle strengthening exercise, balance exercise, and proprioceptive exercise on isokinetic strength and balance in young adults with CAI. Design: Randomized controlled trial. Methods: The subjects were 30 young adults with CAI. The subjects randomly divided into three groups: strengthening exercise, balance exercise, and proprioceptive exercise. They performed each exercise for 20 minutes, three times a week for four weeks. They measured isokinetic strength of dorsiflexor and plantar flexor of 60°/sec and 120°/sec, static and dynamic balance before and after exercise. Results: The isokinetic strengths of dorsiflexor and plantar flexor of 60°/sec and 120°/sec were significantly higher in the strengthening exercise group than in the balance exercise group. The static and dynamic balance was significantly higher in the balance exercise group than in other two groups. Conclusion: Strengthening exercise, balance exercise, proprioceptive exercise can improve the muscle strength for CAI. Strengthening exercise and balance exercise can more improve balance than proprioceptive exercise for CAI.
        5,200원
        3.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: When shorter muscles are restored to normal, non-specific low back pain, which is the mechanism that causes pain along with muscle relaxation, disappears. Among the stretching methods, self-stretching is a good exercise method not only for treatment but also for preventive purposes. Objectives: To find out what is the most effective method of self-stretching, which is often used in treatment and preventive arbitration, which can reduce muscle activity and increase spinal flexibility in patients with non-specific back pain. Design: Randomized controlled trials. Methods: Three self-stretching exercise methods for erector spinae are randomly assigned to 13 people each, and three self-stretching exercise methods are performed for each study subject. Surface electromyography using, was performed to measure the erector spinae muscle activity. flexibility was measured through Trunk flexion test in a standing position. Muscle activity and flexibility were measured before and after stretching. Results: The difference in muscle activity and flexibility in the three groups, including cat stretching, seated stretching, and Reclining stretching, all showed statistically significant differences. There was no statistically significant difference in comparison between the three groups of stretch muscle activity. However, a statistically significant difference was shown in the comparison of the variability between the three groups of flexibility. In a post-mortem analysis comparing the amount of change in flexibility, the flexibility of the seated stretching in the chair increased significantly compared to the cat stretching group. Conclusion: It can be confirmed that the stretching method of the erector spinae, cat stretching, seated stretching, and Reclining stretching, all have positive effects on muscle activity and flexibility.
        4,000원
        4.
        2024.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The transportation of spent nuclear fuel between management stages is expected, and the transportation workers may be exposed to radiation. When transporting spent nuclear fuel, the ALARA principle must be observed for the workers. The objective of this study is to assess a radiation dose for workers transporting spent nuclear fuel using metal overpacks. For this objective, the cask to be handled was selected and the radiation source term was set. Then, the radiation exposure scenario for the transportation workers was defined. Finally, the dose rates for each location of operation were assessed using Monte Carlo simulations, and collective doses were derived for each operation considering the radiation exposure scenario. Each worker performed 11 operations to transport spent nuclear fuel to other facilities and was exposed to a total of 1.138 man-mSv. The operation of removing the bottom shield ring resulted in the highest radiation exposure at 0.503 man-mSv. In contrast, the operation of installing the impact limiter resulted in the lowest radiation exposure at 0.0009 man-mSv. The results of this study can be used to strengthen radiation protection measures for workers transporting spent nuclear fuel in dry storage facilities using metal overpacks.
        4,900원
        5.
        2024.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The increase in radioactive waste increased the demand for transportation to the disposal facility. Prior to transporting radioactive waste, confirming that the potential exposure is insignificant is crucial. Overland transportation risk assessment models were developed tailored to domestic characteristics. Dose assessment using this model requires selecting appropriate factors. However, users may struggle to derive appropriate values, leading to inaccuracies. Additionally, if assessment results show outliers, prioritizing factors for review can be challenging. Therefore, sensitivity analysis is necessary to prioritize factors for accurate assessment. In this study, sensitivity analysis was conducted on the on-link public risk assessment model factors for radioactive waste overland transportation. Initially, assessment models were analyzed by each detailed exposure scenario. Subsequently, uncertainty propagation-based sensitivity analysis methodology was applied. The default values for the assessment model factors were set, and sensitivity analysis was conducted based on road type for maximum individual and collective dose assessment models. For the maximum individual dose model, the distance to the samedirection vehicle was the most sensitive, whereas for the collective dose model, vehicle velocity was the most sensitive. The results of this study can be used as the basic data on radioactive waste transportation risk assessment in Korea in the future.
        4,300원
        6.
        2024.12 구독 인증기관·개인회원 무료
        Efficient and safe maritime navigation in complex and congested coastal regions requires advanced route optimization methods that surpass the limitations of traditional shortest-path algorithms. This study applies Deep Q-Network (DQN) and Proximal Policy Optimization (PPO) reinforcement learning (RL) algorithms to generate and refine optimal ship routes in East Asian waters, focusing on passages from Shanghai to Busan and Ulsan to Daesan. Operating within a grid-based representation of the marine environment and considering constraints such as restricted areas and Traffic Separation Schemes (TSS), both DQN and PPO learn policies prioritizing safety and operational efficiency. Comparative analyses with actual vessel routes demonstrate that RL-based methods yield shorter and safer paths. Among these methods, PPO outperforms DQN, providing more stable and coherent routes. Post-processing with the Douglas-Peucker (DP) algorithm further simplifies the paths for practical navigational use. The findings underscore the potential of RL in enhancing navigational safety, reducing travel distance, and advancing autonomous ship navigation technologies.
        7.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate changes in immunoglobulin G (IgG) concentration, nutrient content, and microbial communities of fresh and heat-treated Holstein colostrum collected from a colostrum bank operated by a local agricultural technology center in Gyeongsangbuk-do, South Korea. Of the 16 colostrum samples, 8 were heated at 60℃ for 30 min under a pressure of 0.9–1 bar. The colostrum samples were stored at −70℃ until use, at which time they were thawed at 50–55℃ in a water bath to analyze IgG levels, chemical composition, and microbiome, which was identified by 16S rRNA gene sequencing using the Illumina MiSeq-PE250 platform. The IgG concentrations were similar in fresh and heat-treated colostrum. The fat, protein, and lactose contents also did not differ in these samples. However, somatic cell count (SCC) was lower in heat-treated colostrum than those in fresh colostrum (p<0.05). At the phylum level for the microbiome of fresh colostrum, Proteobacteria (44.16%) was the most abundant taxa, followed by Bacteroidota (33.26%), Firmicutes (10.04%), Actinobacteriota (7.14%), and a marginal difference in the order of abundance was observed in heat-treated colostrum. At the genus level, bacteria belonging to Sphingomonas, Delftia, Ochrobactrum, Simplicispira, and Lactobacillus were more abundant (p<0.05) in the heat-treated colostrum, while the abundance of Acinetobacter in the fresh colostrum was four times more (p<0.05) than that in the heat-treated colostrum. Our results demonstrated that heating does not affect IgG level and colostrum composition but reduces SCC (p<0.05), suggesting that heat-treated colostrum can potentially be put to further use (e.g., feeding Hanwoo calves) without compromising its quality. Differences in the microbiome between the fresh and heat-treated colostrum were limited. Further studies are required to extensively investigate the quality and safety of colostrum collected from dairy farms to ensure better utilization and processing at a local agricultural technology center.
        4,000원
        8.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the feeding behavior and growth performance of 31 Hanwoo steers (10 months old; 278 ± 36.13 kg) within a precision livestock farming system using Roughage Intake Control (RIC) units for real-time data collection. Feeding behavior traits were derived from RIC database data using R software, with subsequent analysis conducted using SAS software. The results indicated that the steers visited the feed stations every 31.12 ± 11.99 minutes, averaging 11 ± 3.37 visits/day. Each feeding session lasted an average of 5.90 ± 1.55 minutes, resulting in a feed intake rate of 77.98 ± 22.53 g/min. Mean daily feed intake was 4.76 ± 1.36 kg, and body weight increased consistently, reaching an average of 412 ± 43.44 kg, with an average daily gain (ADG) of 1.26 ± 0.38 kg. Pearson correlation analysis revealed a strong relationship between daily feed intake and visit duration (r² = 0.621; p < 0.01) and an inverse correlation between daily feed intake and feed intake duration (r² = −0.445; p < 0.05), indicating behavioral adaptation. These findings highlight the importance of monitoring feeding behavior traits concerning growth performance, enhancing our understanding of individual animal behavior and its implications for productivity while emphasizing the role of advanced technologies in optimizing feed utilization in confined livestock systems.
        4,000원
        9.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, with the development of industrial technology and the increase of young consumers, engine monitoring devices for small ships are rapidly changing from analog devices to LCD-based digital devices. In addition, consumers’ product selection criteria are gradually increasing in favor of luxurious and emotional products rather than price attractiveness. Therefore, in order to develop differentiated products in marketing, it is necessary to find and improve emotionally attractive quality elements. The purpose of this study is to collect 11 customer requirements related to the emotional quality of DGP (Digital Gauge Panel) for small ships through customer interviews and to find attractive quality elements among the emotional qualities of DGP for small ships. 17 design elements were derived by applying QFD to the collected customer requirements, and they were classified into one-dimensional quality, must be quality, and attractive quality through Kano model analysis, and 6 attractive quality elements were confirmed using Timko customer satisfaction index.
        4,200원
        10.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the Fourth Industrial Revolution advances, smart factories have become a new manufacturing paradigm, integrating technologies such as Information and Communication Technology (ICT), the Internet of Things (IoT), Artificial Intelligence (AI), and big data analytics to overcome traditional manufacturing limitations and enhance global competitiveness. This study offers a comprehensive approach by evaluating both technological and economic performance of smart factory Research and Development (R&D) projects, addressing gaps in previous studies that focused narrowly on either aspect. The research combines Latent Dirichlet Allocation (LDA) topic modeling and Data Envelopment Analysis (DEA) to quantitatively compare the efficiency of various topics. This integrated approach not only identifies key research themes but also evaluates how effectively resources are utilized within each theme, supporting strategic decision-making for optimal resource allocation. Additionally, non-parametric statistical tests are applied to detect performance differences between topics, providing insights into areas of comparative advantage. Unlike traditional DEA methods, which face limitations in generalizing results, this study offers a more nuanced analysis by benchmarking efficiency across thematic areas. The findings highlight the superior performance of projects incorporating AI, IoT, and big data, as well as those led by the Ministry of Trade, Industry, and Energy (MOTIE) and small and medium-sized enterprises (SMEs). The regional analysis reveals significant contributions from non-metropolitan areas, emphasizing the need for balanced development. This research provides policymakers and industry leaders with strategic insights, guiding the efficient allocation of R&D resources and fostering the development of smart factories aligned with global trends and national goals.
        5,500원
        11.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 1990년부터 2018년까지의 미국에 상장된 기업들의 기소 자료(Corporate Prosecution Registry)를 바탕으로 기업이 검찰에게 기소를 당했을 시 기업의 재무정책이 어떻게 영향을 받는 지 분석하였다. 먼저 일변량 분석을 통해 기소된 기업들이 주식 시장에서 음(-)의 매수 후 보유 (buy-and-hold) 주식 수익률과 높은 거래 회전율(turnover ratio)을 나타냈다. 더 나아가, 내생 성을 통제하기 위해 다변량 통계분석법 중 하나인 이중차분법(difference-in-differences) 모델을 활용하여 기소 시점을 기준으로 미국 기업의 주식시장에서의 위험도가 급격히 증가하고 현금보 유량이 늘어나는 것으로 나타났다. 또한, 재판 결과에 따라 기업들의 재무정책이 변하는 것을 확인 하였는데 벌금이 낮은 경우 기업들은 현금보유량을 다시 낮추지만 높은 경우에는 현금보유량을 유 지하고 자본지출을 줄이며 인수합병 활동도 줄이는 것으로 나타났다.
        8,900원
        12.
        2024.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, ferric phosphate precursors were prepared by controlling precipitation time, and the resulting LiFe PO4 active materials were thoroughly investigated. Microscale LiFePO4 cathode materials, designed for high energy density at the cell level, were successfully synthesized through a 10 h co-precipitation. As the reaction time increased, smaller primary particles were aggregated more tightly, and the secondary particles exhibited a more spherical shape. Meanwhile, ammonia did not work effectively as a complexing agent. The carbon coated LiFePO4 (LiFePO4/C) synthesized from the 10 h ferric phosphate precursor exhibited larger primary and secondary particle sizes, a lower specific surface area, and higher crystallinity due to the sintering of the primary particles. Enhanced battery performance was achieved with the LiFePO4/C that was synthesized from the precursor with the smaller size, which exhibited the discharge capacity of 132.25 mAh ‧ g-1 at 0.1 C, 70 % capacity retention at 5 C compared with 0.1 C, and 99.9 % capacity retention after the 50th cycle. The better battery performance is attributed to the lower charge transfer resistance and higher ionic conductivity, resulting from smaller primary particle sizes and a shorter Li+ diffusion path.
        4,000원
        13.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This review examines the microstructural and mechanical properties of a Ti-6Al-4V alloy produced by wrought processing and powder metallurgy (PM), specifically laser powder bed fusion (LPBF) and hot isostatic pressing. Wrought methods, such as forging and rolling, create equiaxed alpha (α) and beta (β) grain structures with balanced properties, which are ideal for fatigue resistance. In contrast, PM methods, particularly LPBF, often yield a martensitic α′ structure with high microhardness, enabling complex geometries but requiring post-processing to improve its properties and reduce stress. The study evaluated the effects of processing parameters on grain size, phase distribution, and material characteristics, guiding the choice of fabrication techniques for optimizing Ti-6Al-4V performance in aerospace, biomedical, and automotive applications. The analysis emphasizes tailored processing to meet advanced engineering demands.
        4,000원
        19.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Sarcopenia, characterized by a decrease in physical performance, muscle mass, and strength, is a common complication in patients with stroke, significantly impacting their rehabilitation and quality of life. Objectives: This study aimed to analyze the clinical characteristics associated with sarcopenia in patients with stroke and to identify factors that influence its occurrence. Design: A cross-sectional study. Methods: Data were collected using electronic medical records and assessments, including Korean version of mini-mental state examination (MMSE-K), manual muscle testing, berg balance scale (BBS), functional ambulation category (FAC), and modified barthel index. Sarcopenia was diagnosed based on the Asian working group for sarcopenia 2019 guidelines. Descriptive statistics, chi-square tests, independent t-tests, and logistic regression analyses were used. Results: Of the 82 patients with stroke included in this study, 46 were found to have sarcopenia. Sarcopenic patients had significantly lower body weight, cognitive function (MMSE-K), balance (BBS), walking ability (FAC), and daily living activities (MBI) scores compared to non-sarcopenic patients (P<.05). Logistic regression identified body weight (OR=.852, P=<.001) and cognitive function (OR=.897, P=.035) as significant predictors of sarcopenia. Conclusion: Body weight and cognitive function are crucial in predicting sarcopenia in patients with stroke. These findings suggest the importance of managing body weight and cognitive function to prevent sarcopenia and improve rehabilitation outcomes.
        4,000원
        20.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electrochemical oxidation and reduction reactions are fundamental in various conversion and energy storage devices. Functional materials derived from MOFs have been considered promising as electrical catalysts for ORR, HER, and OER, which can be used in Zinc-air batteries and water electrolysis. Herein, we designed a novel approach to fabricating the ultrafine Co9S8 embedded nitrogen-doped hollow carbon nanocages ( Co9S8@N-HC). The method involved a process of sulfidation of cobalt-based metal–organic frameworks (ZIF67) and then coating them with polypyrrole (PPy). PPy has notable properties such as high electrical conductivity and abundant nitrogen content, rendering it highly promising for catalytic applications. The Co9S8@ N-HC catalyst was successfully synthesized via the carbonization of CoSx@ PPy. Remarkably, the Co9S8@ N-HC catalyst demonstrated exceptional electrocatalytic activity, requiring only low overpotentials of 285 mV and 201 mV at 10 mA cm‒ 2 for OER and HER, respectively, and exhibited high activity for ORR, with an onset potential ( Eonset) of 0.923 V and half-wave potential ( E1/2) of 0.879 V in alkaline media. The electrocatalytic efficiency displayed by Co9S8@ N-HC opens a new line of research on the synergistic effect of MOF-PPy materials on energy storage and conversion.
        4,200원
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