• Steel and Composite Structures
• /
• v.33 no.6
• /
• pp.891-906
• /
• 2019

This study considers the instability behavior of sandwich plates considering magnetorheological (MR) fluid core and piezoelectric reinforced facesheets. As facesheets at the top and bottom of structure have piezoelectric properties they are subjected to 3D electric field therefore they can be used as actuator and sensor, respectively and in order to control the vibration responses and loss factor of the structure a proportional-derivative (PD) controller is applied. Furthermore, Halpin-Tsai model is used to determine the material properties of facesheets which are reinforced by graphene platelets (GPLs). Moreover, because the core has magnetic property, it is exposed to magnetic field. In addition, Kelvin-Voigt theory is applied to calculate the structural damping of the piezoelectric layers. In order to consider environmental forces applied to structure, the visco-Pasternak model is assumed. In order to consider the mechanical behavior of structure, sinusoidal shear deformation theory (SSDT) is assumed and Hamilton's principle according to piezoelasticity theory is employed to calculate motion equations and these equations are solved based on differential cubature method (DCM) to obtain the vibration and modal loss factor of the structure subsequently. The effect of different factors such as GPLs distribution, dimensions of structure, electro-magnetic field, damping of structure, viscoelastic environment and boundary conditions of the structure on the vibration and loss factor of the system are considered. In order to indicate the accuracy of the obtained results, the results are validated with other published work. It is concluded from results that exposing magnetic field to the MR fluid core has positive effect on the behavior of the system.

• Health Policy and Management
• /
• v.20 no.2
• /
• pp.40-52
• /
• 2010

Health insurance fees are set by relative value scales and conversion factors. Since 2008 the conversion factor has been classified into 7 according to the provider type, and a separate contract has been made respectively. As such classification of the conversion factor reflects only the different characteristics of providers, however, further classification to reflect the different cost structures of providers is proposed. Cost varies according to the type of not only providers but also services each provider supply. In fact different cost structures of providers are the result of their different services. This study analyzed the cost structure of medical services to propose a new approach to the classification of the conversion factor. This study analyzed the cost structure of medical services using cost data constructed in the revision study of relative value scales. The cost data consist of doctor's fee, support staff's fee, cost of medical equipments, cost of medical supplies and indirect cost. The proportion of each cost component to the total cost was analyzed in terms of service department and service type. 72 service groups are defined in terms of the combination of service department and service type. Through cluster analysis, 72 service groups were reduced into 7 clusters each of which has a similar cost structure. Conversion factor is contracted annually to reflect the change in the cost of providing medical services. So the classification of conversion factor has to be based on the cost structures of medical services, not the characteristics of providers. Service clusters derived in this study can be used as a new classification for health insurance fee contract.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.661-671
• /
• 2018

Domestic studies on steel plate concrete structures have focused on nuclear structures with high strength. In this study, the SC structure was applied to the general structure, and the SC structure that is advantageous in terms of safety and construction was limited to a special structure. As a basic study for applying SC, this paper proposes basic design information of a SC structure applying cement concrete to plan the structure, which is suitable for eco - friendliness by replacing concrete cement, an important factor in a SC structure, with blast furnace slag. This study examined the compression characteristics and the effective length factor under central compression load. To calculate the effective length factor, the Euler column theory was applied without applying plate theory. The effective length factor was calculated from the yield strength of the steel plate, buckling of the steel plate, and the point at which the concrete was broken. In addition, this study examined whether the maximum compressive strength meets the national and international reference equations with the slenderness ratio (B/t) as a parameter. By analyzing the buckling of the specimen by applying the column theory and selecting the strain of the measured steel plate, the effective length factor was analyzed and compared with the value presented in the reference equation.

• Journal of the Korean Home Economics Association
• /
• v.20 no.4
• /
• pp.83-89
• /
• 1982

The purpose of this study was to analyze the 45 measuring items for the clothing construction in order to observe the factorial structure of items and to extract the common factor and the special unique factor from data. The sample for the study was drawn randomly out of senior high schoolgirls in Seoul urban area. The size of sample was 301 girls between age 16 and 18. The method of analysis was applied by the principal component analysis with orthogonal rotation after extraction of 9 major factors. All of the above data was analyzed by the computer installed at Seoul National University. From these analyses, the major findings can be summerized as follows: 1. The results of factor analysis generally indicated that the first factor was clustered with 15 items, length measures and height measures. The eigenvalue of the first factor was 16.5 and the cumulative percentage of variables 36.6%. 2. The second factor was clustered with width measures, girth measures and weight of 19 items. The eigenvalue of the second factor was 6.5 and the cumulative percentage of variables 51.0%.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.2
• /
• pp.73-79
• /
• 1999

Most of mechanical structures are combined of substructures such as beams and/or plates. There are few systems with unibody structures but are many systems with united body structures. Generally the dynamic a nalysis of whole structures is performed under alternation load. In the structure design, the analysis of each bolted joint is more important than others for zero severity. This paper presents the analysis method of contact stress distribution factor in the bolted joint with variable fastening torque on joints in the structure. At first, a static vibration test was performed to find out a nominal stress of bolt jointed plates from the relationship between natural frequency and nominal stress. Then a contact stress was computed at contact point between bolt and plate in the structure. It is believed that the proposed method has promisiong implications for safer design with index of contact stress distribution factor and has merits for cost-down and saving time at the beginning of vehicle development.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.6
• /
• pp.421-424
• /
• 2013

The Hall factor in a quantum well structure with X or L-type indirect conduction valleys is calculated for various strain conditions. The two-dimensional constant energy surfaces of occupied valleys are proven to be identical. As a result, the Hall factor depends on the relative direction of occupied valleys to the growth direction, regardless of the number of occupied valleys. This work is widely applicable to the two-dimensional structure with indirect conduction minima for any growth direction and under different strain conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.806-808
• /
• 2001

In this thesis, specimens was manufactured in general method annexing PMB-PZT system ceramic, and the following conclusion has been deduced. In XRD, the crystal structure of ceramic has the tetragonal structure which is close to rombohedral structure, and consequently the specimen characterized by MPB was manufactured. According to dopping with xPMB, electromechanical factor(kp) little is changed. kp was maximum value 23.37[%] at xPMB 0.03[mol%]. mechanical quality factor(Qm) was maximum value 237.04 at xPMB 0.03[mo1%].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07b
• /
• pp.578-580
• /
• 2002

In this thesis, specimens was manufactured in general method annexing PMB-PZT system ceramic, and the following conclusion has been deduced. In XRD, the crystal structure of ceramic has the tetragonal structure which is close to rombohedral structure, and consequently the specimen characterized by MPB was manufactured. According to dopping with xPMB, electromechanical factor(kp) little is changed. kp was maximum value 23.37[%] at xPMB 0.03[mol%]. mechanical quality factor(Qm) was maximum value 237,04 at xPMB 0.03[mol%].

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.5
• /
• pp.17-24
• /
• 1996

In this paper, we present a robust performance improvement method for the NLCF(normalized left coprime factor) uncertain structure using loop shaping and the structure singular value. For this, we select weighting functions for a loop shaping considering condition numer, and transform the NLCF uncertain structure into the 4-block structure. However, we can't get a good performance on account of the restriction of weighting functions. To cope with this, we motivate the use of structured singular vlaue in the robust performance improvement procedure. After all, the robust performance improvement can be obtained by a factor W$_{a}$ and a scaling factor of D-K iteration.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.35
• /
• pp.147-178
• /
• 2007

This study clarified a study of relationship of strategic alliance structure factor, partner selection criteria and performance awareness on the container liners alliance. In order to obtain such objective of study existing literature variables suitable to the container liner were perused and extracted. Research models for research development and three study hypothesis were set out and scope of investigation and samples were chosen. The research hypothesis are followings. H1: The factors of strategic alliance motivation influence the performance awareness. H2: The strategic alliance structure factors influence the performance awareness. H3: The factors of partner selection criteria influence the performance awareness. In the result of the empirical study, the hypothesis 1, hypothesis 2 were supported completely and hypothesis 3 was partially supported.