• Health Policy and Management
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• v.22 no.4
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• pp.703-710
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• 2012

Purpose : The aim of this study is to review the current status of healthcare provision and its human resources administrative management and propose a coordinated human resource management plan for the more efficient operations of healthcare organizations. Methods : We reviewed the literature and held discussions with officials from the United States Department of Health and Human Services to survey United States Public Health Service Commissioned Corps operations. In addition, we surveyed the literature to analyze the current structure and responsibilities of governing bodies involved in public healthcare in Korea. Results : In Korea, there are several administrative offices involved in public health: the Ministry of Health and Welfare, the Ministry of Defense, the Environment Ministry and others. Since these diverse agencies don't integrate their operations, it is difficult to grasp their management of both public healthcare services and their personnel. A potential model is the United States Public Health Service Commissioned Corps, a sub-group of the Department of Health and Human Services and an elite team of highly qualified, public health professionals, which coordinates and manages the overall work and personnel of diverse healthcare organizations. Conclusion : We suggest the establishment of a federal level, public health administrative department of human resource management to centralize and coordinate the existing, disparate healthcare administrative agencies.

• Steel and Composite Structures
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• v.34 no.2
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• pp.215-226
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• 2020

The aim of this study is to investigate free vibration of functionally graded porous nanocomposite rectangular plates where the internal pores and graphene platelets (GPLs) are distributed in the matrix either uniformly or non-uniformly according to three different patterns. The elastic properties of the nanocomposite are obtained by employing Halpin-Tsai micromechanics model. The GPL-reinforced plate is modeled using a semi-analytic approach composed of generalized differential quadrature method (GDQM) and series solution adopted to solve the equations of motion. The proposed rectangular plates have two opposite edges simply supported, while all possible combinations of free, simply supported and clamped boundary conditions are applied to the other two edges. The 2-D differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and to implement the boundary conditions. The convergence of the method is demonstrated and to validate the results, comparisons are made between the present results and those reported by well-known references for special cases treated before, have confirmed accuracy and efficiency of the present approach. New results reveal the importance of porosity coefficient, porosity distribution, graphene platelets (GPLs) distribution, geometrical and boundary conditions on vibration behavior of porous nanocomposite plates. It is observed that the maximum vibration frequency obtained in the case of symmetric porosity and GPL distribution, while the minimum vibration frequency is obtained using uniform porosity distribution.

• Steel and Composite Structures
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• v.36 no.1
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• pp.47-62
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• 2020

In this study, free vibration behavior of trapezoidal sandwich plates with porous core and two graphene platelets (GPLs) reinforced nanocomposite outer layers are presented. The distribution of pores and GPLs are supposed to be functionally graded (FG) along the thickness of core and nanocomposite layers, respectively. The effective Young's modulus of the GPL-reinforced (GPLR) nanocomposite layers is determined using the modified Halpin-Tsai micromechanics model, while the Poisson's ratio and density are computed by the rule of mixtures. The FSDT plate theory is utilized to establish governing partial differential equations and boundary conditions (B.C.s) for trapezoidal plate. The governing equations together with related B.C.s are discretized using a mapping- generalized differential quadrature (GDQ) method in the spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained by GDQ method. Validity of current study is evaluated by comparing its numerical results with those available in the literature. A special attention is drawn to the role of GPLs weight fraction, GPLs patterns of two faces through the thickness, porosity coefficient and distribution of porosity on natural frequencies characteristics. New results show the importance of this permeates on vibrational characteristics of porous/GPLR nanocomposite plates. Finally, the influences of B.C.s and dimension as well as the plate geometry such as face to core thickness ratio on the vibration behaviors of the trapezoidal plates are discussed.

• Steel and Composite Structures
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• v.36 no.1
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• pp.1-16
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• 2020

In steel-concrete composite beams, to improve the cracking resistance of the concrete slab in the hogging moment region, a new type of connector in the interface, named uplift-restricted and slip-permitted screw-type (URSP-S) connector has been proposed. This paper focuses on the behavior of steel-concrete composite beams with URSP-S connectors. A total of three beam specimens including a simply supported beam with URSP-S connectors and two continuous composite beams with different connectors arrangements were designed and tested. More specifically, one continuous composite beam was equipped with URSP-S connectors in negative moment region and traditional shear studs in other regions. For comparison, the other one was designed with only traditional shear studs. The failure modes, crack evolution process, ultimate capacities, strain responses at different locations as well as the interface slip of the three tested specimens were measured and evaluated in-depth. Based on the experimental study, the research findings indicate that the larger slip deformation is allowed while using URSP-S connectors. Meanwhile, the tensile stress reduces and the cracking resistance of the concrete slab improves accordingly. In addition, the overall stiffness and strength of the composite beam become slightly lower than those of the composite beam using traditional shear studs. Moreover, the arrangement suggestion of URSP-S connectors in the composite beam is discussed in this paper for its practical design and application.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2343-2348
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• 2008

Ant algorithm is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, we propose the improved $AS_{rank}$ algorithms. The original $AS_{rank}$ algorithm accomplishes a pheromone updating about only the paths which will be composed of the optimal path is higher, but, the paths which will be composed the optimal path is lower does not considered. In this paper, The proposed method evaporate the pheromone of the paths which will be composed of the optimal path is lowest(worst tour path), it is reducing the probability of the edges selection during next search cycle. Simulation results of proposed method show lower average search time and average iteration than original ACS.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.33-40
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• 2011

An efficient method for the rapid micropropagation of Camptotheca acuminata from axillary buds was established by application of various plant growth regulators. Among various cytokinins, $0.5mg\;L^{-1}$ BA showed the best performance on shoot multiplication, number average multiple shoots up to 10.8. The propagated shoot cuttings in vitro were elongated on NN basal medium without plant growth regulators. The secondary multiple shoots were induced at the site of initially induced buds. Rooting was induced directly near the base of the shoot on half-strength NN medium containing $0.5mg\;L^{-1}$ of IBA, whereas high concentration of $1.0mgL^{-1}$ IBA could induce callus at the base of the shoot. The camptothecin content, anticancer compound of the micropropagated plants was contained in various tissues. Camptothecin contents were 1.8 and $2.5mg\;g^{-1}$ dry weight in stems from propagated in vitro and mother plant, respectively. This result may be used to develop strategies for large-scale propagation of elite C. acuminata trees.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.250-257
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• 2008

Knowledge of genetic diversity and of the genetic relationships among elite breeding materials has had a significant impact on the improvement of crops. In maize, this information is particularly useful in i) planning crosses for hybrid and line development, ii) in assigning lines to heterotic groups and iii) in plant variety protection. We have used the SSR technique to study the genetic diversity and genetic relationships among 76 Korean waxy corn accessions, representing a diverse collection from throughout Korea. Assessment of genetic diversity among members of this group was conducted using 30 microsatellite markers. Among these 30 microsatellite markers, we identified a total of 127 alleles (with an average of 4.2 and a range of between 2 and 9 alleles per locus). Gene diversity at these 30 microsatellite loci varied from 0.125 to 0.795 with an average of 0.507. The cluster tree generated with the described microsatellite markers recognized two major groups with 36.5% genetic similarity. Group I includes 63 inbred lines, with similarity coefficients of between 0.365 and 0.99. Group II includes 13 inbred lines, with similarity coefficients of between 0.45 and 0.85. The present study indicates that the 30 microsatellite loci chosen for this analysis are effective molecular markers for the assessment of genetic diversity and genetic relationships between Korean waxy corn accessions. Specifically, this study's assessment of genetic diversity and relationships between a set of 76 Korean waxy corn inbred lines will be helpful for such activities as planning crosses for hybrid and line development and association mapping analyses of maize breeding programs in Korea.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.330-339
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• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.59-67
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• 2003

An efficient plant regeneration system was developed for Hordeum vulgare L. cv Baegdong - an important Korean cultivar. The protocol was based on a series of experiments involving the sizes of mature embryos and the culture media. The embryo size is found to be critical for the establishment of embryogenic callus. Embryos of 1.1-1.5 mm size showed a much higher ability to produce embryogenic callus capable of regenerating green plants. The auxins picloram and dicamba proved effective in inducing callus from mature embryos. $2.5\;m;I^{-1}$ dicamba and $4.0\;mg\;I^{-1}$ picloram in Murashige and Skoog's (MS) medium was optimum for the induction of primary callus. The induced primary callus was loose and friable which ultimately developed into creamy white and compact callus after transferring into the fresh medium. Multiple shoots were induced in the MS medium supplemented with $6.0\;g\;I^{-1}$ maltose, $20\;mg\;I^{-1}$ sorbitol, $0.5\;mg\;I^{-1}$ 2, 4-D and $1.0\;mg\;I^{-1}$ kinetin and the rate was 6.5 shoots per embryo. Regenerated plants were hardy and developed roots rapidly in the medium containing $0.2\;I^{-1}$ IBA. This efficient plant regeneration system provides a foundation for generating transgenic plants of this important barley cultivar.

• Structural Engineering and Mechanics
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• v.60 no.6
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• pp.939-952
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• 2016

A compression to tensile load transforming (CTT) device was developed to determine indirect tensile strength of concrete material. Before CTT test, Particle flow code was used for the determination of the standard dimension of physical samples. Four numerical models with different dimensions were made and were subjected to tensile loading. The geometry of the model with ideal failure pattern was selected for physical sample preparation. A concrete slab with dimensions of $15{\times}19{\times}6cm$ and a hole at its center was prepared and subjected to tensile loading using this special loading device. The ratio of hole diameter to sample width was 0.5. The samples were made from a mixture of water, fine sand and cement with a ratio of 1-0.5-1, respectively. A 30-ton hydraulic jack with a load cell applied compressive loading to CTT with the compressive pressure rate of 0.02 MPa per second. The compressive loading was converted to tensile stress on the sample because of the overall test design. A numerical modeling was also done to analyze the effect of the hole diameter on stress concentrations of the hole side along its horizontal axis to provide a suitable criterion for determining the real tensile strength of concrete. Concurrent with indirect tensile test, the Brazilian test was performed to compare the results from two methods and also to perform numerical calibration. The numerical modeling shows that the models have tensile failure in the sides of the hole along the horizontal axis before any failure under shear loading. Also the stress concentration at the edge of the hole was 1.4 times more than the applied stress registered by the machine. Experimental Results showed that, the indirect tensile strength was clearly lower than the Brazilian test strength.