• Advances in nano research
• /
• v.8 no.2
• /
• pp.149-156
• /
• 2020

The present paper explores forced vibrational properties of porosity-dependent functionally graded (FG) cylindrical nanoshells exposed to linear-type or triangular-type impulse load via classical shell theory (CST) and nonlocal strain gradient theory (NSGT). Employing such scale-dependent theory, two scale factors accounting for stiffness softening and hardening effects are incorporated in modeling of the nanoshell. Two sorts of porosity distributions called even and uneven have been taken into account. Governing equations obtained for porous nanoshell have been solved through inverse Laplace transforms technique to derive dynamical deflections. It is shown that transient responses of a nanoshell are affected by the form and position of impulse loading, amount of porosities, porosities dispensation, nonlocal and strain gradient factors.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1999.04a
• /
• pp.191-192
• /
• 1999

• 대한예방의학회:학술대회논문집
• /
• 1995.10a
• /
• pp.363-364
• /
• 1995

• Proceedings of the KAIS Fall Conference
• /
• 2010.11b
• /
• pp.523-527
• /
• 2010

본 논문에서는 Jazz는 물론 여러 음악 장르에서 사용되는 Diminished Scale을 Major7, Minor7, Dominant7 Chord에서의 활용 방법을 Jazz의 Improvisation의 관점에서 연구한다. 또한 Upper Structure와의 연계뿐 아니라 Out Line 적인 요소까지 각 코드 기능별 Diminished Scale의 활용을 연구한다.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.31 no.2
• /
• pp.94-103
• /
• 2008

This study measured technology transfer efficiency for public institutes. The study made use of DEA being one of the non-parametric linear programming to evaluate technology transfer efficiency for public institutes and to measure technology efficiency, pure technical efficiency and scale efficiency. The measurement of the technology transfer efficiency for public institutes was as follows: The cause of the technology transfer inefficiency was affected by pure technical inefficiency more than by scale inefficiency. Public institutes' RTS(Return To Scale) value varied depending upon the features of the organizations than the features of the regions. Public research institutes' RTS value is more effective than universities' RTS value. We compared the RTS group with the RTS of Projected DMU groups. The RTS group had constant returns to scale effect while the RTS of the Projected DMU had increasing returns to scale effect. The technology transfer efficiency of public institutes varied depending upon the features of the organizations and regions : The technology transfer efficiency of public institutes were as follows : public research institutes at the metropolitan area, public research institutes at the local areas, universities at the metropolitan area and universities at the local areas. In other words, the technology transfer efficiency was affected by organizational characteristics more than by regional characteristics at the place where public institutes were located.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.3
• /
• pp.92-98
• /
• 2017

The rapid growth of engineering technology and the emergence of systemized and large-scale engineering systems have resulted in complexity and uncertainty throughout the lifecycle activities of engineering systems. This complex and large-scale engineering system consists of numerous components, but system failure can be caused by failure of any one of a number of components. There is a real difficulty in managing such a complex and large-scale system as a part. In order to efficiently manage the system and have high reliability, it is necessary to structure a system with a complex structure as a sub-system. Also, in the case of a system in which cause of failures exist at the same time, it is required to identify the correlation of the components lifetime and utilize it for the design policy or maintenance activities of the system. Competitive risk theory has been used as a theory based on this concept. In this study, we apply the competitive risk theory to the models with combined structure of series and parallel which is the basic structure of most complex engineering systems. We construct a competing risks model and propose a mathematical model of net lifetime and crude lifetime for each cause of failure, assuming that the components consisting a parallel system are mutually dependent. In addition, based on the constructed model, the correlation of cause of failure is mathematically analyzed and the hazard function is derived by dividing into net lifetime and crude lifetime.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.3
• /
• pp.29-38
• /
• 2015

In this paper, scale efficiencies and relative efficiencies of R&D projects in Industrial Technology Program, sponsored by Ministry of Trade, Industry and Energy, Korea, are calculated and compared. For the process, various DEA (Data Envelopment Analysis) models are adopted as major techniques. For DEA, two stage input oriented models are utilized for calculating the efficiencies. Next, the calculated efficiencies are grouped according to their subprograms (Industrial Material, IT Fusion, Nano Fusion, Energy Resources, and Resources Technology) and recipient types (Public Enterprise, Large Enterprise, Medium Enterprise, Small Enterprise, Lab., Univ., and etc.) respectively. Then various subprograms and recipient types are compared in terms of scale efficiencies (CCR models) and relative efficiencies (BCC models). In addition, the correlation between the 1st stage relative efficiencies and the 2nd stage relative efficiencies is calculated, from which the causal relationship between them can be inferred. Statistical analysis shows that the amount of input, in general, should increase in order to be scale efficient (CCR models) regardless of the subprograms and recipient types, that the 1st and 2nd stage relative efficiencies are different in terms of the programs and recipient types (BCC models), and that there is no significant correlation between the 1st stage relative efficiencies and the 2nd stage relative efficiencies. However, the results should be used only as reference because the goal each and every subprogram has is different and the situation each and every recipient type faces is different. In addition, the causal link between the 1st stage relative efficiencies and the 2nd relative efficiencies is not considered, which, in turn, is the limitation of this paper.

• Elastomers and Composites
• /
• v.52 no.2
• /
• pp.99-104
• /
• 2017

Due to the depletion of fossil oil and the increasing oil price, bio-plastic is currently topical. Bio-based plastics are synthesized from plant resources, unlike conventional petroleum-based counterparts. Therefore, the former minimizes global warming and reduces carbon dioxide emission. Fossil polycarbonate (PC)has good mechanical and optical properties, but its synthesis requires bisphenol-A and phosgene gas, which are toxic to humans. To address these problems, the fused deposition 3D printing process (hereafter, FDM) is studied using environmentally-friendly and high-strength bio-based PC. A comparisonof the environmental impact and tensile strength of fossil PC versus bio-based PC is presented herein, demonstrating that bio-based PC is more environmentally-friendly with higher tensile strength than fossil PC. The advantages of bio-based PC are applied in the FDM process for the fabrication of environmentally-friendly baby toys.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.4
• /
• pp.337-343
• /
• 2009

Noncatalytic partial oxidation of methane for producing synthesis gas was studied in a lab-scale experimental apparatus. Partial oxidation developed for high-temperature, fuel-rich combustion and it is exothermic process. but Steam reforming and Caron reforming is highly endothermic process to need much energy. Noncatalytic partial oxidation of methane is affected by temperature and equivalent ratio, so we studied effect about composition of synthesis gas at lab scale reactor. We used electronic heater to control the temperature of reactor. The quality of synthesis gas is improved and reduced heat value to require at Noncatalytic partial oxidation because the reacting temperature is lower at oxy condition.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.2821-2830
• /
• 2014

This study was carried out to define gazelle industry through preceded research for gazelle firm & gazelle region, in order to discover high-growth industries. Gazelle industry is 'employees per company is more than ten people, and over the past five years, within top 10% by Birch employment growth index'. According to the definition of gazelle industry, Chungnam gazelle 105 industries were chosen. Then, analyzed whether Chungnam gazelle industries has competitiveness compared with nation and each city of Chungnam. In addition, typology to industrial development stage was devised by developing of business scale quotient(BQ) and industrial growth rate(IG). And development strategies of Chungnam gazelle industries was proposed case by industrial development stage.