• 한국융합학회논문지
• /
• 제13권4호
• /
• pp.307-313
• /
• 2022

차량 실내소음이 엔진의 고출력화와 경량화로 인해 더욱 심각해져 엔진진동의 저감의 중요성이 높아지고 있다. 최근 엔진진동 저감의 대표적인 방법으로 밸런스샤프트 부착이 제시되고 있다. 밸런스샤프트는 피스톤과 콘로드 등의 왕복운동에서 발생하는 진동을 임의의 편심질량을 이용하여 상쇄시키는 장치이다. 따라서 밸런스샤프트는 연비향상 및 차량의 승차감을 동시에 향상시킬 수 있다. 본 논문은 엔진구조로 인해 발생하는 관성력을 유도하고 이를 상쇄하기 위한 밸런스샤프트의 불평형량과 형상을 제시한다. 제시된 두가지 형상의 밸런스샤프트를 ADAMS 다물체동역학 모델로 구현하고, 이를 동역학 시뮬레이션을 통해 실제 거동상태에서의 관성력의 저감을 확인하였다.

• 대한의용생체공학회:의공학회지
• /
• 제44권1호
• /
• pp.80-84
• /
• 2023

Electrodes are one of the types of biosensors capable of measuring bio signals, such as electrocardiogram (ECG) and electromyogram (EMG) signals. These electrodes are used in various fields and offer the advantage of being able to measure ECG signals without the need for skin attachment, compared to Ag/AgCl electrodes. The purpose of this study was to evaluate the efficacy of conductive textile electrodes in collecting ECG signals in a bed-like environment. Three adult participants were involved, and a total of 30 minutes of ECG signals were collected for each participant. The collected ECG signals were analyzed to determine the heart rate, normLF and a comparison was made between the conductive textile electrodes and Ag/AgCl electrodes. As a result, the change in heart rate and normLF could be observed, and in particular, the difference between the two electrodes decreased. This study confirmed that conductive textile electrodes can effectively collect ECG signals in a bed-like environment. It is hoped that this research will lead to the development of a system that can detect various sleep-related diseases through the use of these electrodes.

• 문화기술의 융합
• /
• 제8권5호
• /
• pp.341-349
• /
• 2022

본 연구에서는 아동기 트라우마를 겪은 성인여성 생존자의 트라우마 영향으로 인한 정서경험에 대하여 심층적으로 탐구하고자 하였다. 이를 위해 아동기에 트라우마를 겪은 기혼 성인여성을 대상으로 심층면접을 진행하였다. 수집된 자료는 Colaizzi의 현상학적 연구방법을 통해 분석을 실시하였다. 연구결과, '자신을 지킬 수 없는 아이', '트라우마된 아동기 외상', '불안정애착과 착한아이 증후군', '대인관계의 어려움', '자녀양육의 어려움', '신체화증상', '잃어 버린 나를 찾아서' 의 7개의 범주가 도출되었다. 아울러 본 연구에서는 양육자로부터 직접 학대를 경험한 외상과 동생의 사고를 목격 경험한 가족인 형제의 외상이 트라우마로 진행하는 두 사례를 비교와 대조를 통해 가족내에서 자녀들이 겪어야만 했던 심리 내적인 경험과 부모와 아동기에 형성된 불안정 애착으로 인한 관계외상과 이를 치유해 가는 성장 경험을 이해하려는 것이 목적이다. 아동기 트라우마를 겪은 성인여성들의 삶의 전반에 반영된 부정적 부적응적 정서경험에 대한 연구결과를 통해 건강한 자아 회복과 정서적으로 잘 적응하며 살아갈 수 있는 토대를 마련하였다고 볼 수 있다.

• Computers and Concrete
• /
• 제32권5호
• /
• pp.487-498
• /
• 2023

The present study investigated the flexural behavior of reinforced concrete (RC) beams strengthened with an ultrahigh performance concrete (UHPC) panel having various thicknesses. Two fabrication methods were introduced in this study; one was the direct casting of UHPC onto the bottom surface of the RC beams (I-series), and the other was the attachment of a prefabricated UHPC panel using an adhesive (E-series). UHPC panels having thicknesses of 10, 30, 50, and 70 mm were applied to RC beams, and these specimens were subjected to four-point loading to assess the effect of the UHPC thickness on the flexural strengthening of RC beams. The test results indicated that the peak strength and initial stiffness were vastly enhanced with an increase in the thickness of the UHPC panel, showing an improved energy dissipation capacity. In particular, the peak strength of the E-series specimens was higher than that of I-series specimens, showing high compatibility between the RC beam and the UHPC panel. The experimental test results were comparatively explored with a discussion of numerical analysis. Numerical analysis results showed that the predictions are in fair agreement with experimental results.

• 한국안전학회지
• /
• 제38권5호
• /
• pp.36-42
• /
• 2023

In this study, 50 ABE-type hard hats were procured from five certified commercial manufacturers, and shock absorption tests were conducted in accordance with Protective Equipment Safety Certification Notice No. 2020-35. The tests were performed under both high- and low-temperature conditions, adhering to safety helmet testing standards. The highest shock transmission ranges were recorded in the tests, with an average energy range of 2,600-4,108 N at high temperatures and 2,316-3,991 N at low temperatures. All five hard hat models demonstrated a maximum transmitted impact force below 4,450 N, without any loss of cap and attachment functionality, confirming their compliance with performance standards. Furthermore, we evaluated the side impact performance of the safety helmets of each company, with an average range of 4,722-5,267 N. Company A exhibited the lowest measurement at 4,722 N. Comparing these results with international safety standards and the national shock absorption test criteria, it was observed that the maximum transmitted shock value using government-specified impact weight falls within the range of 4,450-5,000 N. However, it was noted that developed countries have established specific standards for the side impact forces on safety helmets, which are legally mandated. Consequently, it is imperative for South Korea to enhance its safety helmet side impact performance test methodology to align with domestic standards in the future.

• Animal Bioscience
• /
• 제37권4호
• /
• pp.555-566
• /
• 2024

Objective: This study aimed to assess the genetic parameters and accuracy of genomic predictions for twenty-four linear body conformation traits and overall conformation scores in Korean Holstein dairy cows. Methods: A dataset of 2,206 Korean Holsteins was collected, and genotyping was performed using the Illumina Bovine 50K single nucleotide polymorphism (SNP) chip. The traits investigated included body traits (stature, height at front end, chest width, body depth, angularity, body condition score, and locomotion), rump traits (rump angle, rump width, and loin strength), feet and leg traits (rear leg set, rear leg rear view, foot angle, heel depth, and bone quality), udder traits (udder depth, udder texture, udder support, fore udder attachment, front teat placement, front teat length, rear udder height, rear udder width, and rear teat placement), and overall conformation score. Accuracy of genomic predictions was assessed using the single-trait animal model genomic best linear unbiased prediction method implemented in the ASReml-SA v4.2 software. Results: Heritability estimates ranged from 0.10 to 0.50 for body traits, 0.21 to 0.35 for rump traits, 0.13 to 0.29 for feet and leg traits, and 0.05 to 0.46 for udder traits. Rump traits exhibited the highest average heritability (0.29), while feet and leg traits had the lowest estimates (0.21). Accuracy of genomic predictions varied among the twenty-four linear body conformation traits, ranging from 0.26 to 0.49. The heritability and prediction accuracy of genomic estimated breeding value (GEBV) for the overall conformation score were 0.45 and 0.46, respectively. The GEBVs for body conformation traits in Korean Holstein cows had low accuracy, falling below the 50% threshold. Conclusion: The limited response to selection for body conformation traits in Korean Holsteins may be attributed to both the low heritability of these traits and the lower accuracy estimates for GEBVs. Further research is needed to enhance the accuracy of GEBVs and improve the selection response for these traits.

• Journal of Veterinary Science
• /
• 제25권3호
• /
• pp.43.1-43.13
• /
• 2024

Importance: Haemaphysalis longicornis is an obligate blood-sucking ectoparasite that has gained attention due its role of transmitting medically and veterinary significant pathogens and it is the most common tick species in Republic of Korea. The preferred strategy for controlling ticks is a multi-antigenic vaccination. Testing the efficiency of a combination antigen is a promising method for creating a tick vaccine. Objective: The aim of the current research was to analyze the role of subolesin and enolase in feeding and reproduction of H. longicornis by gene silencing. Methods: In this study, we used RNA interference to silence salivary enolase and subolesin in H. longicornis. Unfed female ticks injected with double-stranded RNA targeting subolesin and enolase were attached and fed normally on the rabbit's ear. Real-time polymerase chain reaction was used to confirm the extent of knockdown. Results: Ticks in the subolesin or enolase dsRNA groups showed knockdown rates of 80% and 60% respectively. Ticks in the combination dsRNA (subolesin and enolase) group showed an 80% knockdown. Knockdown of subolesin and enolase resulted in significant depletion in feeding, blood engorgement weight, attachment rate, and egg laying. Silencing of both resulted in a significant (p < 0.05) reduction in tick engorgement, egg laying, egg hatching (15%), and reproduction. Conclusions and Relevance: Our results suggest that subolesin and enolase are an exciting target for future tick control strategies.

• Journal of Periodontal and Implant Science
• /
• 제53권5호
• /
• pp.376-387
• /
• 2023

Purpose: Peri-implantitis (PI) is an inflammatory condition associated with the destruction of bone tissue around a dental implant, and diode lasers can be used to treat this disease. In this study, we aimed to evaluate the effectiveness of a 940-nm diode laser for the nonsurgical treatment of PI. Methods: Twenty patients (8 women and 12 men) were enrolled in a split-mouth randomized controlled study. In the control group (CG), mechanical debridement with titanium curettes accompanied by airflow was performed around the implants. The test group (TG) was treated similarly, but with the use of a diode laser. Clinical measurements (plaque index, gingival index [GI], probing pocket depth [PPD], bleeding on probing [BOP], clinical attachment level, and interleukin-1β [IL-1β] in the peri-implant crevicular fluid) were evaluated and recorded at baseline and 3 months. IL-1β levels were determined using the enzyme-linked immunosorbent assay method. Results: The symptoms were alleviated in both groups at 3 months as assessed through clinical measurements. GI, BOP, and PPD were significantly lower in the TG than in the CG (P<0.05). The IL-1β level increased post-treatment in both groups, but this increase was only statistically significant (P<0.05) in the CG. Conclusions: The diode laser enabled improvements in clinical parameters in the periimplant tissue. However, it did not reduce IL-1β levels after treatment. Further studies about the use of diode lasers in the treatment of PI will be necessary to evaluate the effects of diode lasers in PI treatment.

• Journal of the Korean Wood Science and Technology
• /
• 제17권2호
• /
• pp.34-64
• /
• 1989

포장(包裝) 용적(容積) 감소에 따른 수송비(輸送費) 절감(節減) 효과(效果)가 있어 조립시(組立式) 탁자류(卓子類) 가구(家具)의 제작(製作)에 널리 쓰이는 CBA(corner block with anchor bolt) 접합방식(接合方式)은 일정기간(一定期間) 사용(使用)함에 따라 접합부위(接合部位)가 약해지고 그 결과(結果) 구조(構造)가 불안정(不安定)하게 되는 반강접합(半剛接合)(semi-rigid joint) 특유(特有)의 결점(缺點)도 지니고 있다. 따라서 본(本) 연구(硏究)에서는 CBA 접합(接合) 강도(强度)에 영향하는 주요(主要) 설계(設計) 인자(因子)로서 side rail 규격, corner block의 side rail에의 부착시(時) 보강재(補强材)의 효과(效果) 및 corner block관통 anchor bolt의 사용(使用) 수(數) 그리고 corner block의 형태등(等)의 평가(評價)를 하기 위해 22개(個)의 접합군(接合群) 별(別)로 총(總) 88개(個)의 table section 시험체(試驗體)를 제작(製作)한 후(後)그들의 강성(剛性) 계수(係數)(Z - 값) 및 유효강도(有效强度)를 수평 하중(荷重)에 의한 변형측정(變形測定) 실험(實驗)을 통해 결정(決定)한 후 설계(設計) 인자별(因子別) 효과(效果)를 비교 분석(分析)하였다. 분석결과(分析結果), side rail의 높이 증대(增大) 및 corner block 부착시(時) PVAc 수지(樹脂)의 사용효과(使用效果)가 뚜렷하여 유효강도(有效强度)의 유의적(有意的) 향상(向上)을 나타냈고 anchor bolt의 효과(效果) 역시 2개 사용시(使用時)가 1개 사용시(使用時) 보다 훨씬 큰 것으로 나타났다. 또 side rail 높이 와 anchor bolt 사용(使用) 수(數)간에는 상호작용(相互作用) 효과(效果)도 있었다. 그러나 side rail의 두께 효과(效果)는 22mm에서 25mm로 증대(增大)시켰을때 뚜렷한 상승 경향(傾向)은 보여주지 못했다. 한편 corner block의 형태는 MDF를 주재료(主材料)로 사용(使用)한 탁자(卓子) 설계시(設計時)는 두께 25mm, 높이 100mm의 side rail에 PVAc 수지(樹脂)로 보강(補强)하고 mitered corner block에 2개(個)의 anchor bolt를 관통시킨 경우가 유효강도(有效强度) 3171.7 kgf-cm로 22개의 접태군(接台群)들 중 최대치(最大値)를 나타냄으로써 miter type이 rectangular type보다 바람직한 것으로 나타났다. 결론적(結論的)으로 자재(資材)의 효과적(效果的) 이용(利用)을 통한 생산비(生産費) 절감(節減)과 동시(同時)에 구조(構造)의 안정(安定)된 강도적(强度的) 측면(側面)을 고려할 때, 두께 22mm, 높이 75mm의 MDF side rail에 mitered corner block을 PVAc 수지(樹脂)와 나사못을 이용하여 부착한 후(後) 2개(個)의 anchor bolt를 관통시키는 방법(方法)을 가장 합리적(合理的)인 MDF 사용(使用) 조립시(組立式) 탁자(卓子) 설계(設計) 방안(方案)으로 제시(提示)하는 바이다.

• 유통과학연구
• /
• 제14권2호
• /
• pp.113-121
• /
• 2016

Purpose - The purpose of this study is to identify team commitment affecting employees' innovative activities and factors affecting team commitment including empowerment by leaders and job enrichment factors. In other words, so as to explain outcome variables of innovative activities, this study aims to emphasize employees' attachment roles towards their groups within nomological network, and identify the motives encouraging employees' innovative activities. The research purpose is significant due to the realistic situation of hotel industry. The reason why innovative activities are important can be found in recent changes of business environment. Also, unlike other various studies on precedence factors encouraging employees' innovative activities, this study classified those precedence factors into job and leader characteristics, and it emphasized the importance of team commitment as the process that job and leader characteristics are connected to innovative activities. Research design, data and methodology - The survey for this study was conducted during October 6^th ~ November 10^th in 2014 to the employees who are working in 5-star hotels in Korea. As for the selection of hotels and sampling method, convenience sampling method was used to the employees in 5-star hotels. Self-report method was used in the survey, judging that the employees' characteristics would be relatively homogeneous. 311 questionnaires were distributed in total, and 275 reponses were collected. After excluding the missing and unreliable responses, 245 questionnaires were used in the research. SPSS and AMOS programs were used for the analysis. Results - First, empowering leadership had positive effects on hotel employees' team commitment. It indicates that hotel employees are more committed to their team when their leaders set examples, provide information, and involve employees in decision-making process. Second, as a result of the relationship analysis in task diversity, task significance, task identity and team commitment, task diversity and task significance had significant effect on team commitment, while task identity had no significant effect on team commitment. It indicates that team commitment is enhanced when the employees can conduct diverse types of jobs and get more opportunities to talk with the guests. Also, the repetition for the same jobs in hotel rooms and the space for preparing food and beverage do not lead to team commitment, even though the employees fulfill their duties to the end. Third, hotel employees' team commitment has positive effect on their innovative activities. It indicates that employees voluntarily conduct innovative activities when they are attached to their team and identifies themselves with the team. Conclusions - There are theoretical and practical implications in this study. First, in terms of the theoretical perspective, this study proposes structural framework in team commitment, and it identifies the psychological mechanism in team commitment from the aspect of social exchange, which resulted in identification of precedence factors related to team commitment. In addition, this study presents new possibilities for relevant studies about team commitment by examining the effect on team commitment when the importance of innovative activities is emphasized in recent business environment.