• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.237-240
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• 2009

1844년 Rochdale Pioneers는 소비자 협동조합을 만들고 그 첫 번째 상점을 열었다. 이 소비조합을 통해 지역 주민에게 양질의 식품을 저렴한 가격에 제공했다. 이러한 유럽의 전통적이고 좌파성향의 경제적 분배이념이 발전하여 유럽의 사회적 기업의 발판이 되었다. 뿐 만 아니라 1991년 이탈리아에서는 주주나 소유주의 이익 산출보다는 공동체 또는 구성원을 위하는 사회적 경제 개념의 협동조합이 시작되었다. 1980년 아쇼카 재단의 설립자 빌 드레이튼은 슘페트에 의해 처음 소개된 '기업가정신'을 한 단계 높은 차원으로 끌어올렸다. 그는 기업가 정신을 사회적 혁신에도 적용하여 사회의 난제에 대해서도 창조적 파괴를 시도하자는 뜻에서 사회적'과 '기업가'를 합성하여 사회적 기업가 정신이라고 사용했다. 이러한 사회적 기업의 발전 과정에서 보면 유럽과 미국의 인식의 차이를 우리는 느낄 수 있다. 유럽의 경우는 좌파적 성향이 담겨져 있다. 유럽의 사회적 기업은 협동조합에서 알 수 있듯이 공평한 분배 개념에의 접근이다. 그에 비해서 미국의 경우는 우파적 성향이 강하다. 미국은 기업가 정신이 투철한 기업가가 많은 부를 축척하고 이렇게 축척된 부의 분배 과정에서 사회적 가치가 강조된다. 이러한 사회적 기업을 가능하게 하는 요인 중 하나가 사회적 자본으로 불리는 네트워크이다. 본 연구는 25개의 사회적 기업 실증을 통하여 생존을 위한 전략적 차원에서 네트워크의 다양성과 강도가 사회적 기업의 기업생존과 고용성장, 매출성장 나아가 권한위임에 정의 관계가 있음을 검증하였다.

• Industrial Engineering and Management Systems
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• v.16 no.1
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• pp.92-102
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• 2017

In this paper, we consider a typical health care system via the help of Wireless Sensor Network (WSN) for wireless patient tracking. The wireless patient tracking module of this system performs localization out of samples of Received Signal Strength (RSS) variations and tracking through a Particle Filter (PF) for WSN assisted by multiple transmit-power information. We propose a modified PF, Kullback-Leibler Distance (KLD)-resampling PF, to ameliorate the effect of RSS variations by generating a sample set near the high-likelihood region for improving the wireless patient tracking. The key idea of this method is to approximate a discrete distribution with an upper bound error on the KLD for reducing both location error and the number of particles used. To determine this bound error, an optimal algorithm is proposed based on the maximum gap error between the proposal and Sampling Important Resampling (SIR) algorithms. By setting up these values, a number of simulations using the health care system's data sets which contains the real RSSI measurements to evaluate the location error in term of various power levels and density nodes for all methods. Finally, we point out the effect of different power levels vs. different density nodes for the wireless patient tracking.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2425-2433
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• 2018

This study investigates a new organic based material and its dielectric and mechanical properties. It is a comprehensive nanocomposite comprising a combination of various types of nanofillers with hydrophobic silica nanoparticles (AEROSIL R 974) as a matrix modifier and a polyamide nano nonwoven textile, Ultramid-Polyamide 6, pulped in the electrostatic field as a dielectric barrier. The polymer matrix is an epoxy network based on diglycidyl ether of bisphenol A (DGEBA) and cycloaliphatic diamine (Laromine C260). The designed nanocomposite material is an alternative to the conventional three-component composites containing fiberglass and mica with properties that exceed current electroinsulating systems (volume resistivity on the order of $10^{16}{\Omega}{\cdot}m$, dissipation factor tan ${\delta}=4.7{\cdot}10^{-3}$, dielectric strength 39 kV/mm).

• Computers and Concrete
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• v.10 no.6
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• pp.557-573
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• 2012

This paper discusses the combined application of two different techniques, Neural Networks (NN) and Principal Component Analysis (PCA), for improved prediction of concrete properties. The combination of these approaches allowed the development of six neural networks models for predicting slump and compressive strength of concrete with mineral additives such as blast furnace slag, fly ash and silica fume. The Back-Propagation Multi-Layer Perceptron (BPMLP) with Bayesian regularization was used in all these models. They are produced to implement the complex nonlinear relationship between the inputs and the output of the network. They are also established through the incorporation of a huge experimental database on concrete organized in the form Mix-Property. Thus, the data comprising the concrete mixtures are much correlated to each others. The PCA is proposed for the compression and the elimination of the correlation between these data. After applying the PCA, the uncorrelated data were used to train the six models. The predictive results of these models were compared with the actual experimental trials. The results showed that the elimination of the correlation between the input parameters using PCA improved the predictive generalisation performance models with smaller architectures and dimensionality reduction. This study showed also that using the developed models for numerical investigations on the parameters affecting the properties of concrete is promising.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.167-183
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• 2013

Methods for estimating structural reliability using probability ideas are well established. When the residual ultimate strength of a buried pipeline is exceeded the limit, breakage becomes imminent and the overall reliability of the pipe distribution network is reduced. This paper is concerned with estimating structural failure of underground flexible pipes due to corrosion induced excessive deflection, buckling, wall thrust and bending stress subject to externally applied loading. With changes of pipe wall thickness due to corrosion, the moment of inertia and the cross-sectional area of pipe wall are directly changed with time. Consequently, the chance of survival or the reliability of the pipe material is decreased over time. One numerical example has been presented for a buried steel pipe to predict the probability of failure using Hasofer-Lind and Rackwitz-Fiessler algorithm and Monte Carlo simulation. Then the parametric study and sensitivity analysis have been conducted on the reliability of pipeline with different influencing factors, e.g. pipe thickness, diameter, backfill height etc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1785-1801
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• 2017

In recent years, image encryption algorithms have been developed rapidly in order to ensure the security of image transmission. With the assistance of our previous work, this paper proposes a novel chaotic image encryption algorithm based on self-adaptive model and feedback mechanism to enhance the security and improve the efficiency. Different from other existing methods where the permutation is performed by the self-adaptive model, the initial values of iteration are generated in a novel way to make the distribution of initial values more uniform. Unlike the other schemes which is on the strength of the feedback mechanism in the stage of diffusion, the piecewise linear chaotic map is first introduced to produce the intermediate values for the sake of resisting the differential attack. The security and efficiency analysis has been performed. We measure our scheme through comprehensive simulations, considering key sensitivity, key space, encryption speed, and resistance to common attacks, especially differential attack.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.177-177
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• 2008

The effect of several $SiO_2-B_2O_3-Al_2O_3$-R(R;Ca, Sr, Ba) borosilicate glass system on sintering behavior, dielectric properties and mechanical properties of glass/ceramic composites were investigated. The amount of '+2 valency' metal elements(Ca, Sr, Ba) were examined in LTCC composite of low k glass with cordierite filler. It was sintered for 60minutes in temperature range from 850C to 950. Properties of frit and glass/ceramic composites were analyzed by DTA, XRD, SEM, Network Analyzer, UTM and so on. Dielectric constant ($\varepsilon_r$) and $Q{\times}f_0$ (Q) of the composite with 50% glass contents demonstrated $\varepsilon_r$ = 5.4 $Q{\times}f_0$ = 1600 GHz. Sintering was complete and maximum bending strength of 160MPa was obtained.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.277-282
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• 2004

In a hardened concrete, diffusion of oxygen, carbon dioxide, aggressive ions, and moisture from the environment to the concrete takes place through the pore network. It is well known that making dense cement matrix enhances the durability of concrete as well as all the characteristics including strength of concrete. In this paper,9 mix concretes with water to cementitious material ratio (40,45, and $50\%$) and replacement ratio of GGBFS (40 and $60\%$ of cement by weight) were studied on the micro-pore structure by mercury intrusion porosimetry and the accelerated chloride diffusion test by potential difference. From the results the average pore diameter and accelerated chloride diffusivity of concrete were ordered NPC > G4C > G6C. It is concluded that there is a good correlation between the average pore diameter and the chloride diffusivity, and the mineral admixtures has a filling effect, which increases the tortuosity of pore and makes large pores finer, on the pore structure of cement matrix due to the latent hydraulic reaction with hydrates of cement.

• Asia pacific journal of information systems
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• v.12 no.2
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• pp.137-162
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• 2002

As the ERP system become recognized as a strategic weapon of a firm, the way how to implement the system successfully has been an important issue for both practitioners and the academic community. The objective of this research is to identify the critical success factors influencing the implementation of the ERP system and to suggest the tasks to be considered first for the effective implementation of the system. The results from the analysis of data collected from the 169 firms among those which have implemented either the Oracle package or the SAP package in Korea are as follows. The important factors for the successful implementation of the ERP system include the strength of rivalry among competing firms; the degree to which information systems are matured; the information systems strategy of a firm; the support and concern from the top; and the technical openness between the ERP system and the legacy system such as network, hardware, and software. The tasks to be considered first for the effective implementation of the ERP system cover the same degree of feeling between labor and management on the threat to survive; the formulation of information systems strategy at the strategic level; CEO's strong will and resolution; the process automation and informatization of a firm; and the infrastructure including intranet and databases.

• International Journal of CAD/CAM
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• v.12 no.1
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• pp.20-28
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• 2012

Finite Element Analysis (FEA) is often used to identify local stress/strain concentrations where a component is likely to fail. In order to reduce the degree of strain concentration, component thickness can be increased in those regions, or a stronger material can be used. In short fiber reinforced composite materials, strength and stiffness can be increased through proper fiber alignment. The field-aided microtailoring (FAiMTa) process is one promising method for doing this. FAiMTa uses principles of dielectrophoresis to preferentially align particles or fibers within a matrix. To achieve the preferred fiber orientation, an interdigitated electrode network must be integrated into the mold halves which can be fabricated by additive manufacturing (AM) processes. However, the process of determining the preferred fiber arrangements and electrode locations can be very challenging. This paper presents algorithms to semi-automate the interdigitated electrode design process. The algorithm has been implemented in the Solidworks CAD system and is demonstrated in this paper.