• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.10a
• /
• pp.775-780
• /
• 2013

In recent years, a notebook like an ultrabook gets thinner. Its thickness causes problems in cooling fan performance, system installation condition, and so on. In this study, we installed a small turbofan in notebook system with very narrow gap in order to generate similar condition to a real product. Experiments were performed to measure the fan's performance and the flow and noise characteristics, its results were compared with computational ones. Prediction of P-Q curve using CFD showed under about 5% error in high flow rate and its trend was agreed with experimental one over the flow field. Experimental data to measure the noise at a distance of 100 mm from a rotation axis direction of an impeller corresponded well with computational ones of broadband and BPF noise. The noise experiments to measure at a distance of 100 mm from a rotation axis direction of an impeller corresponded well with computational ones of broadband and BPF noise. Especially, tip part of impeller blade and part of exit and bottom near in an analysis by a commercial program(FlowNoise).

• The Pure and Applied Mathematics
• /
• v.20 no.4
• /
• pp.233-242
• /
• 2013

Certain interesting single (or double) infinite series associated with hypergeometric functions have been expressed in terms of Psi (or Digamma) function ${\psi}(z)$, for example, see Nishimoto and Srivastava [8], Srivastava and Nishimoto [13], Saxena [10], and Chen and Srivastava [5], and so on. In this sequel, with a view to unifying and extending those earlier results, we first establish two relations which some double infinite series involving hypergeometric functions are expressed in a single infinite series involving ${\psi}(z)$. With the help of those series relations we derived, we next present two functional relations which some double infinite series involving $\bar{H}$-functions, which are defined by a generalized Mellin-Barnes type of contour integral, are expressed in a single infinite series involving ${\psi}(z)$. The results obtained here are of general character and only two of their special cases, among numerous ones, are pointed out to reduce to some known results.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2001.05a
• /
• pp.238-239
• /
• 2001

The egg-yolk precursor vitellogenin(VTG) is secreted by the liver of female and male fish, in response to estrogenic compound. Carp(Cryprinus carpio) vitellogenin of one major protein is 160kDa, two minor proteins is 110kDa and 170kDa. We were induced vitellogenin by inject of 17-estradiol and purified in a two step procedure by separating it from plasma protein precipitated by 35% saturated ${(NH_4)}_2SO_4$ and then from the remainder by Mono-Q chromatography. We found major carp(Cyprinus carpio) vitellogenin band at 160kDa. Effect of different concentration of oestrogen on vitellogenin synthesis in carp(Cyprinus carpio) exposed for 4 weeks. Show differential effects on vitellogenin synthesis 7 days after treatment. Plasma vitellogenin was measured 3 times for each by an enzyme linked immunosorbent assay(ELISA). ELISA was developed for the detection of the egg yolk precursor vitellogenin in plasma of carp(Cyprinus carpio). The ELISAS performance was optimized and characterized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.531-534
• /
• 2004

In Recent, it became necessary to develope the technology about electrodeless fluorescent lamp according to demand of the electodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electordeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter. So it is of the utmost importance to design antena and inverter Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electordeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.251-252
• /
• 2019

본 논문에서는 기존의 AGV보다 높은 안전성과 Task Scheduling을 바탕으로 한 효율적인 AGV를 제안하였다. AGV는 객체인식 알고리즘인 YOLO로 다른 AGV를 인식하여 자동으로 피난처로 들어간다. 또한 마커인식 알고리즘인 ar_markers를 이용하여 그 위치가 적재소인지 생산 공정인지를 판단하여 각 마커마다 멈추고 피난처에 해당하는 Marker가 인식되고 다른 AGV가 인식되면 피난처로 들어가는 동작을 한다. 이 모든 로그는 Mobius를 이용해 Spring기반의 웹 홈페이지로 확인할 수 있으며, 작업스케줄 명령 또한 웹 홈페이지에서 내리게 된다. 위 작업스케줄은 외판원, 벨만-포드 알고리즘을 적용한 뒤 강화학습알고리즘 중 하나인 DQN을 이용해 최적 값을 도출해 내고 그 값을 DB에 저장해 AGV가 움직일 수 있도록 한다. 본 논문에서는 YOLO와 Marker 그리고 웹을 사용하는 AGV가 기존의 AGV에 비해 더욱 가볍고 큰 시설이 필요하지 않다는 점에서 우수함을 보인다.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.3
• /
• pp.100-106
• /
• 2021

Typical implants are not specified the screw structure and the surface process according to the bone quality of the human body. The purpose of this study is to complement the shortcomings of the existing implant surface processing method. It is to propose a surface processing method that increases the adhesion between the implant and bone tissue by increasing the surface area per unit area of the implant. It is very important to establish precise and systematic process parameters when surface treatment of implants using lasers. Therefore, we intend to develop a process so that the implant can be a biocompatible structure using a Q-switching Nd:YAG laser with a wavelength of 1.06um. Implant surface treatment technology through this study will be used in the industry.

• Asia-Pacific Journal of Business
• /
• v.12 no.3
• /
• pp.71-85
• /
• 2021

Purpose - Prior studies have found that the characteristics of managers, corporate governance structure, corporate social responsibility and so on affect firm value. This study explores whether managerial overconfidence affects firm value through empirical analysis. Design/methodology/approach - Korean-listed non-financial companies from 2011 - 2017 are collected as the research sample. Firm value is measured by Tobin's Q, and managerial overconfidence is measured using a composite index encompassing various financial data. OLS and fixed effect model are used to investigate the relationship between managerial overconfidence and firm value. Findings - Managerial overconfidence is positively associated with firm value. Additional analysis reveals the following: (1) In the three subsamples of large, backbone, and small- and medium-sized enterprises, managerial overconfidence is beneficial to firm values. (2) Managerial overconfidence increases firm value on the t+1 year. Research implications or Originality - We use a comprehensive index with higher trust and feasibility to measure manager overconfidence and empirically confirm that managerial overconfidence can become a factor to improve firm value. Thus, it is necessary for shareholders to adopt an objective and neutral attitude and reasonably understand the psychological characteristics of managers when selecting CEOs. In addition, it is necessary to continue to optimize the measurement method of managerial overconfidence.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.204-212
• /
• 2022

Recently, the Korean government has been actively promoting the smart city as their strategic agenda. However, to build smart cities that are greener, the authors believe it is essential to rapidly transit conventional energy sources such as fossil fuels to renewable energy. Although there is a big potential for Offshore wind in Korea, there has not been a full-scale commercial offshore wind farm until today. Since Korea is relatively a new market compared to the EU, it can be risky for developers. The authors will introduce risk management best practices in the offshore wind industry applicable to the Korean environment. This paper will mainly introduce an offshore wind project size of 99 MW. The project is expecting a Finance Close (FC) in Q3 2022, so the project team has prepared a risk register with over 150 risks and levers throughout the project lifecycle. Overall risks include risks with Development Expenditure (DEVEX) impact, a Capital Expenditure (CAPEX) impact, and an Operating Expenditure (OPEX) impact. Based on the identified risks, a more qualitative assessment of Cost and Schedule Impact was conducted. In conclusion, a Monte Carlo simulation was performed to propose a quantitative risk assessment to evaluate a benchmark contingency of the project cost.

• Fashion & Textile Research Journal
• /
• v.25 no.3
• /
• pp.333-345
• /
• 2023

The rising demand for fashion do-it-yourself (DIY) products that cater to individual preferences and which allow for creative expression has highlighted the need for systematic organization within the clothing society. This study addresses this gap by identifying and discussing clothing DIY packages and proposes a systematic package model comprising essential raw materials, commercial patterns, and production instructions. Four key elements have been emphasized to differentiate and enhance the product. Firstly, highly practical commercial patterns have been developed to facilitate easy transformations - from blouses to dresses. Furthermore, the versatility of these patterns has been optimized so as to allow their utilization as outerwear, increasing their efficiency. Secondly, to accommodate diverse body shapes, the package offers six different sizes, providing users with a range of options tailored to their specific measurements. Thirdly, detailed production instructions are provided, supplemented by a Q&A bulletin board. The instructions are available in a printed format, featuring actual photographs on A4 paper, while video production instructions are accessible via a QR code, ensuring comprehensive guidance. Lastly, the basic package comprises clothing patterns, production instructions, fabrics, and labels, providing a complete toolkit for clothing DIY enthusiasts. This study aims to contribute to the development of the hobby sewing field and to establish a practical resource for the clothing DIY package industry.

• The Korean Journal of Physiology and Pharmacology
• /
• v.27 no.2
• /
• pp.187-196
• /
• 2023

Transient receptor potential canonical (TRPC) channels are non-selective calcium-permeable cation channels. It is suggested that TRPC4β is regulated by phospholipase C (PLC) signaling and is especially maintained by phosphatidylinositol 4,5-bisphosphate (PIP₂). In this study, we present the regulation mechanism of the TRPC4 channel with PIP₂ hydrolysis which is mediated by a channel-bound PLCδ1 but not by the G_qPCR signaling pathway. Our electrophysiological recordings demonstrate that the Ca²⁺ via an open TRPC4 channel activates PLCδ1 in the physiological range, and it causes the decrease of current amplitude. The existence of PLCδ1 accelerated PIP₂ depletion when the channel was activated by an agonist. Interestingly, PLCδ1 mutants which have lost the ability to regulate PIP₂ level failed to reduce the TRPC4 current amplitude. Our results demonstrate that TRPC4 self-regulates its activity by allowing Ca²⁺ ions into the cell and promoting the PIP₂ hydrolyzing activity of PLCδ1.