• 마이크로전자및패키징학회지
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• 제6권2호
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• pp.13-21
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• 1999

Flip chip assembly directly on organic boards offers miniaturization of package size as well as reduction in interconnection distances resulting in a high performance and cost-competitive Packaging method. This paper describes the investigation of alternative low cost flip-chip mounting processes using electroless Ni/Au bump and anisotropic conductive adhesives/films as an interconnection material on organic boards such as FR-4. As bumps for flip chip, electroless Ni/Au plating was performed and characterized in mechanical and metallurgical point of view. Effect of annealing on Ni bump characteristics informed that the formation of crystalline nickel with $Ni_3$P precipitation above $300^{\circ}C$ causes an increase of hardness and an increase of the intrinsic stress resulting in a reliability limitation. As an interconnection material, modified ACFs composed of nickel conductive fillers for electrical conductor and non-conductive inorganic fillers for modification of film properties such as coefficient of thermal expansion(CTE) and tensile strength were formulated for improved electrical and mechanical properties of ACF interconnection. The thermal fatigue life of ACA/F flip chip on organic board limited by the thermal expansion mismatch between the chip and the board could be increased by a modified ACA/F. Three ACF materials with different CTE values were prepared and bonded between Si chip and FR-4 board for the thermal strain measurement using moire interferometry. The thermal strain of ACF interconnection layer induced by temperature excursion of $80^{\circ}C$ was decreased with decreasing CTEs of ACF materials.

• KIEE International Transactions on Power Engineering
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• 제5A권1호
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• pp.85-92
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• 2005

In this paper, Nash equilibriums of generation markets are investigated using a game theory application for simplified competitive electricity markets. We analyze the characteristics of equilibrium states in N-company spot markets modeled by uniform pricing auctions and propose a new method for obtaining Nash equilibriums of the auction. We assume that spot markets are operated as uniform pricing auctions and that each generation company submits its bids into the auction in the form of a seal-bid. Depending on the bids of generation companies, market demands are allocated to each company accordingly. The uniform pricing auction in this analysis can be formulated as a non-cooperative and static game in which generation companies correspond to players of the game. The coefficient of the bidding function of company-n is the strategy of player-n (company-n) and the payoff of player-n is defined as its profit from the uniform price auction. The solution of this game can be obtained using the concept of the non-cooperative equilibrium originating from the Nash idea. Based on the so called residual demand curve, we can derive the best response function of each generation company in the uniform pricing auction with N companies, analytically. Finally, we present an efficient means to obtain all the possible equilibrium set pairs and to examine their feasibilities as Nash equilibriums. A simple numerical example with three generation companies is demonstrated to illustrate the basic idea of the proposed methodology. From this, we can see the applicability of the proposed method to the real-world problem, even though further future analysis is required.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1992-1998
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• 2007

자궁 경부 세포진 영상의 효과적인 세포핵 영역 추출과 인식 및 분류를 위해서는 세포진 영상의 배경 그리고 세포핵과 세포질 영역의 정확한 구분이 중요하다. 본 논문에서는 자궁 경부 세포진 영상에서 세포핵 영역과 배경을 효과적으로 분할하기 위 해 Median 필터를 적용하여 전체적인 영상의 명암값을 보정한 후, Gaussian 필터를 적용하여 그레이 영상에서 존재하는 잡음을 제거한다. Kapur 방법을 통해 배경과 세포의 엔트로피 누적 확률을 이용하여 영상을 이진화 한다. 자궁 경부진 영상에서는 군집화된 세포 영 역 이 빈번하게 나타난다. 군집화가 심화된 세포영역에서는 그 영역의 평균 명암도 값을 이용하여 세밀하게 영역을 재분할 한다. 그런 후, 미세잡음을 제거하기 위해 $3{\times}3$ 마스크를 적용하여 미세한 잡음을 제거 한 후, 8 방향 윤곽선 추적 알고리즘을 적용하여 분할된 영역에서 세포들의 후보영역을 추출한다. 추출된 세포영역은 크기, 면적 비율, 핵 외곽의 방향성 정보를 이용하여 정상 세포와 암세포를 인식 및 분류한다. 실험 결과에서는 제안된 방법의 성능이 전문의와 소견과 비교적 근접한 것을 보여준다.

• Bulletin of the Korean Chemical Society
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• 제2권2호
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• pp.71-75
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• 1981

Vacuum ultraviolet photolysis of ethyl bromide was studied at 104.8-106.7 nm (11.4-11.6 eV) in the pressure range of 0.2-18.6 torr at $25^{\circ}$ using an argon resonance lamp with and without additives, i.e., NO and He. Since the ionization potential of $CH_3CH_2Br$ is lower than the photon energy, the competitive processes between the photoionization and the photodecomposition were also investigated. The observations indicated that 50% of absorbed light leads to the former process and the rest to the latter one. In the absence of NO the principal reaction products for the latter process were found to be $CH_4, C_2H_2, C_2H_4, C_2H_6, and C_3H_8$. The product quantum yields of these reaction products showed two strikingly different phenomena with an increase in reactant pressure. The major products, $C_2H_4$ and $C_2H_6$, showed positive effects with pressure whereas the effects on minor products were negative in both cases, i.e., He and reactant pressures. Addition of NO completely suppresses the formation of all products except $C_2H_4$ and reduces the $C_2H_4$ quantum yield. These observations are interpreted in view of existence of two different electronically excited states. The initial formation of short-lived Rydberg transition state undergoes HBr molecular elimination and this state can across over by collisional induction to a second excited state which decomposes exclusively by carbon-bromine bond fission. The estimated lifetime of the initial excited state was ${\sim}4{\times}10^{-10}$ sec. The extinction coefficient for $CH_3CH_2Br$ at 104.8-106.7 nm and $25{\circ}$ was determined to be ${varepsilon} = (1/PL)ln(I_0/I_t) = 2061{\pm}160atm^{-1}cm6{-1}$ with 95% confidence level.

• 한국산학기술학회논문지
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• 제20권2호
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• pp.587-592
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• 2019

최근 들어 소프트웨어 경쟁력을 확보하기 위한 기술이 스마트폰과 IoT 기술이 맞물려 새로운 사업으로 확장되고 있어 소프트웨어 기술에 대한 중요성은 더욱 부각 되고 있다. 따라서 글로벌 소프트웨어 산업의 주도권 확보와 융합형 소프트웨어 인재 양성을 위해 우수한 소프트웨어 개발 인력의 필요성은 점점 더 증가하고 있다. 본 논문에서는 융합형 소프트웨어 산업 인력 확대를 위해 소프트웨어를 필수 교과로 운영한 사례를 기반으로 소프트웨어에 대한 기본 인식과 소프트웨어 개발의 필요성 그리고 소프트웨어 개발을 위한 코딩 능력 향상에 대하여 분석한다. 분석 결과, 코딩 능력 향상을 위한 실습방법 중 학습자 중심에서 진행된 기술적 내용은 소프트웨어에 대한 인식과 개발의 필요성 측면에서 긍정적인 효과를 나타내고 있으며 코딩 능력 향상에 중요한 요소가 되는 것으로 분석되었다. 본 논문에 나타난 연구 결과에서 프로그램 개발의 필요성과 능동적인 참여는 실무 능력 향상을 위해 매우 중요한 부분이라는 것을 나타내고 있으며, 이러한 결과는 소프트웨어 개발 능력 향상을 위한 방법론 측면에서 의미 있는 결과를 제시하고 있음을 알 수 있다.

• Steel and Composite Structures
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• 제43권5호
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• pp.523-532
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• 2022

Turbocharger technology is one of the ways to survive in a competitive market that is facing increasing demand for fuel and improving the efficiency of vehicle engines. Turbocharging allows the engine to operate at close to its maximum power, thereby reducing the relative friction losses. One way to optimally understand the behavior of a turbocharger is to better understand the heat flow. In this paper, a 1.7 liter, 4 cylinder and 16 air valve gasoline engine turbocharger with compressible, viscous and 3D flow was investigated. The purpose of this paper is numerical investigation of the number of heat transfer in gasoline engines turbochargers under 3D flow and to examine the effect of different types of coatings on its performance; To do this, modeling of snail chamber and turbine blades in CATIA and simulation in ANSYS-FLUENT software have been used to compare the results of turbine with experimental results in both adiabatic and non-adiabatic (heat transfer) conditions. It should be noted that the turbine blades are modeled using multiple rotational coordinate methods. In the experimental section, we simulated our model without coating in two states of adiabatic and non-adiabatic. Then we matched our results with the experimental results to prove the validation of the model. Comparison of numerical and experimental results showed a difference of 8-10%, which indicates the accuracy and precision of numerical results. Also, in our studies, we concluded that the highest effective power of the turbocharged engine is achieved in the adiabatic state. We also used three types of SiO₂, Sic and Si₃N₄ ceramic coatings to investigate the effect of insulating coatings on turbine shells to prevent heat transfer. The results showed that SiO₂ has better results than the other two coatings due to its lower heat transfer coefficient.

• 한국지반공학회논문집
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• 제24권10호
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• pp.5-15
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• 2008

본 연구의 목적은 연약지반개량을 위한 수평배수층 재료로 순환골재의 적용가능성을 검증함에 있다. 최근 모래의 수급불균형이 초래되고 있으며, 이는 단순히 가격 상승의 문제에서 그치는 것이 아닌 전체 공정의 지연을 초래하게되어 문제의 심각성이 크다. 이러한 상황에서 순환골재는 그 수요를 충족시킬 수 있는 적절한 대체재료로 인식되고 있으며, 이를 검증하기 위해 우선 이미 제정된 각종기준과 규정을 찾아 비교 정리하였고, 다음으로 기존의 수평배수층 재료인 모래와의 공학적 특성에 대한 비교 및 검토를 시행하였다. 결과로써 순환골재는 모래에 비해 큰 투수계수 및 단위중량으로 인해 수평배수층으로써의 대부분 기준을 만족하였으며, 클로깅에 대한 문제는 수평배수층 상부에 필터층을 추가 설치하는 방안으로 해결할 수 있어, 현장적용이 가능한 것으로 판단되었다. 또한 모래에 비해 순환골재의 구입단가가 상대적으로 낮아 공사비 절감이 가능하여, 수평배수층 재료로 순환골재는 매우 경쟁력있는 대체재료라 할 수 있다.

• Membrane and Water Treatment
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• 제15권2호
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• pp.67-78
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• 2024

In this study, a nickel hexacyanoferrate and manganese dioxide-polyacrylonitrile (NM-PAN) composite was synthesized and used for the sorptive removal of Co²⁺, Sr²⁺, and Cs⁺ Cs⁺ in radioactive laundry wastewater. Single- and multi-solute competitive sorptions onto NM-PAN were investigated. The Freundlich (Fr), Langmuir (Lang), Kargi-Ozmıhci (K-O), Koble-Corrigan (K-C), and Langmuir-Freundlich (Lang-Fr) models satisfactorily predicted all the single sorption data. The sorption isotherms were nonlinearly favorable (Freundlich coefficient, N_F = 0.385-0.426). Cs⁺ has the highest maximum sorption capacity (q_mL = 0.855 mmol g^-1) for NM-PAN compared to Co²⁺ and Sr²⁺, wherein the primary mechanism was the physical process (mainly ion-exchange). The competition between the metal ions in the binary and ternary systems reduced the respective sorption capacities. Binary and ternary sorption models, such as the ideal adsorbed solution theory (IAST) model coupled with single sorption models of IAST-Fr, IAST-K-O, IAST-K-C and IAST-Lang-Fr, were fitted to the experimental data; among these, the IAST-Freundlich model showed the most satisfactory prediction for the binary and ternary systems. The presence of cationic surfactants highly affected the sorption on NM-PAN due to the increase in distribution coefficients (K_d) of Co²⁺ and Cs⁺.

• 마케팅과학연구
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• 제18권1호
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• pp.115-139
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• 2008

IMF이후 경쟁의 심화와 적대적인 경영환경에 효과적으로 대응하고자 많은 호텔기업들이 구조조정을 실시해오고 있다. 이러한 구조조정은 인력감축을 동반하기 때문에 구조조정 과정에서 공정성을 지각하는데, 인력감축에서 살아남은 생존자들이 인력감축의 절차나 실무에서 불공정성을 지각할 때 상사에 대한 신뢰감이나 조직유효성을 감소시키는 것으로 나타났다. 따라서 본 연구는 호텔기업을 대상으로 구조조정 이후 살아남은 생존자를 대상으로 정리해고의 공정성 지각이 경영진의 신뢰, 직무만족 및 조직몰입에 어떠한 영향을 미치는지를 살펴보고자 하는 것이다. 이러한 연구목적을 달성하기 위해 실증분석을 실시한 결과 잔류종업원들은 구조조정 과정에서 절차 공정성 및 분배 공정성을 높게 지각 할수록 경영진에 대한 신뢰감과 조직 몰입이 높아지는 것으로 나타났다. 그러나 구조조정 과정에서 절차 공정성을 높게 지각할수록 직무만족은 높아지는 것으로 나타났지만, 분배 공정성은 직무만족과는 인과관계가 없는 것으로 나타났다. 또한 구조조정 과정에서의 경영진에 대한 신뢰감이 높아질수록 직무만족이나 조직몰입은 높아지는 것으로 나타났다.

• Asia pacific journal of information systems
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• 제23권3호
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• pp.25-53
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• 2013

This study analyzes the effect of Computer Aided Innovation (CAI) to improve R&D Capabilities empirically. Survey was distributed by e-mail and Google Docs, targeting CTO of 235 SMEs. 142 surveys were returned back (rate of return 60.4%) from companies. Survey results from 119 companies (83.8%) which are effective samples except no-response, insincere response, estimated value, etc. were used for statistics analysis. Companies with less than 50billion KRW sales of entire researched companies occupy 76.5% in terms of sample traits. Companies with less than 300 employees occupy 83.2%. In terms of the type of company business Partners (called 'partners with big companies' hereunder) who work with big companies for business occupy 68.1%. SMEs based on their own business (called 'independent small companies') appear to occupy 31.9%. The present status of holding IT system according to traits of company business was classified into partners with big companies versus independent SMEs. The present status of ERP is 18.5% to 34.5%. QMS is 11.8% to 9.2%. And PLM (Product Life-cycle Management) is 6.7% to 2.5%. The holding of 3D CAD is 47.1% to 21%. IT system-holding and its application of independent SMEs seemed very vulnerable, compared with partner companies of big companies. This study is comprised of IT infra and IT Utilization as CAI capacity factors which are independent variables. factors of R&D capabilities which are independent variables are organization capability, process capability, HR capability, technology-accumulating capability, and internal/external collaboration capability. The highest average value of variables was 4.24 in organization capability 2. The lowest average value was 3.01 in IT infra which makes users access to data and information in other areas and use them with ease when required during new product development. It seems that the inferior environment of IT infra of general SMEs is reflected in CAI itself. In order to review the validity used to measure variables, Factors have been analyzed. 7 factors which have over 1.0 pure value of their dependent and independent variables were extracted. These factors appear to explain 71.167% in total of total variances. From the result of factor analysis about measurable variables in this study, reliability of each item was checked by Cronbach's Alpha coefficient. All measurable factors at least over 0.611 seemed to acquire reliability. Next, correlation has been done to explain certain phenomenon by correlation analysis between variables. As R&D capabilities factors which are arranged as dependent variables, organization capability, process capability, HR capability, technology-accumulating capability, and internal/external collaboration capability turned out that they acquire significant correlation at 99% reliability level in all variables of IT infra and IT Utilization which are independent variables. In addition, correlation coefficient between each factor is less than 0.8, which proves that the validity of this study judgement has been acquired. The pair with the highest coefficient had 0.628 for IT utilization and technology-accumulating capability. Regression model which can estimate independent variables was used in this study under the hypothesis that there is linear relation between independent variables and dependent variables so as to identify CAI capability's impact factors on R&D. The total explanations of IT infra among CAI capability for independent variables such as organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability are 10.3%, 7%, 11.9%, 30.9%, and 10.5% respectively. IT Utilization exposes comprehensively low explanatory capability with 12.4%, 5.9%, 11.1%, 38.9%, and 13.4% for organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability respectively. However, both factors of independent variables expose very high explanatory capability relatively for technology-accumulating capability among independent variable. Regression formula which is comprised of independent variables and dependent variables are all significant (P<0.005). The suitability of regression model seems high. When the results of test for dependent variables and independent variables are estimated, the hypothesis of 10 different factors appeared all significant in regression analysis model coefficient (P<0.01) which is estimated to affect in the hypothesis. As a result of liner regression analysis between two independent variables drawn by influence factor analysis for R&D capability and R&D capability. IT infra and IT Utilization which are CAI capability factors has positive correlation to organization capability, process capability, human resources capability, technology-accumulating capability, and collaboration capability with inside and outside which are dependent variables, R&D capability factors. It was identified as a significant factor which affects R&D capability. However, considering adjustable variables, a big gap is found, compared to entire company. First of all, in case of partner companies with big companies, in IT infra as CAI capability, organization capability, process capability, human resources capability, and technology capability out of R&D capacities seems to have positive correlation. However, collaboration capability appeared insignificance. IT utilization which is a CAI capability factor seemed to have positive relation to organization capability, process capability, human resources capability, and internal/external collaboration capability just as those of entire companies. Next, by analyzing independent types of SMEs as an adjustable variable, very different results were found from those of entire companies or partner companies with big companies. First of all, all factors in IT infra except technology-accumulating capability were rejected. IT utilization was rejected except technology-accumulating capability and collaboration capability. Comprehending the above adjustable variables, the following results were drawn in this study. First, in case of big companies or partner companies with big companies, IT infra and IT utilization affect improving R&D Capabilities positively. It was because most of big companies encourage innovation by using IT utilization and IT infra building over certain level to their partner companies. Second, in all companies, IT infra and IT utilization as CAI capability affect improving technology-accumulating capability positively at least as R&D capability factor. The most of factor explanation is low at around 10%. However, technology-accumulating capability is rather high around 25.6% to 38.4%. It was found that CAI capability contributes to technology-accumulating capability highly. Companies shouldn't consider IT infra and IT utilization as a simple product developing tool in R&D section. However, they have to consider to use them as a management innovating strategy tool which proceeds entire-company management innovation centered in new product development. Not only the improvement of technology-accumulating capability in department of R&D. Centered in new product development, it has to be used as original management innovative strategy which proceeds entire company management innovation. It suggests that it can be a method to improve technology-accumulating capability in R&D section and Dynamic capability to acquire sustainable competitive advantage.