• Journal of Korean Library and Information Science Society
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• v.44 no.3
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• pp.125-152
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• 2013

The purpose of this study is to construct a substantive theory that described and explained how pregnant women are seeking information in context of pregnancy. A qualitative design based on the method of grounded theory was utilized. In-depth interviews were conducted with 16 pregnant women, selected by theoretical sampling who receiving antenatal care 3 different university hospitals. The interview data were transcribed and systematically analyzed according to the open coding, axial coding and selective coding. 'Increasing Sense of Self-Control over Pregnancy' was the core category for describing and guiding the process of seeking information during the pregnancy. To construct a theory of 'Increasing Sense of Self-Control over Pregnancy' in this study, eight hypothetical statement were generated from the relationships among the core category and the other categories, thus four patterns were derived as follows: 'Desperately Seeking', 'Actively Seeking', 'Unconcernedly Seeking', 'Resignedly Seeking'. The implications of the findings are discussed in terms of development of LIS theory in Korea, theory development of information behavior, education for LIS, and information service practice. The suggestions for further research are provided.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.583-588
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• 2009

Network intrusion detection system (NIDS) monitors all incoming packets in the network and detects packets that are malicious to internal system. The NIDS should also have ability to update detection rules because new attack patterns are unpredictable. Incorporating FPGAs into the NIDS is one of the best solutions that can provide both high performance and high flexibility comparing with other approaches such as software solutions. In this paper we propose and design a novel approach, prefix sharing parallel pattern matcher, that can not only minimize additional resources but also maximize the processing performance. Experimental results showed that the throughput for 16-bit input is twice larger than for 8-bit input but the used LEs/Char in FPGA increases only 1.07 times.

• Tunnel and Underground Space
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• v.9 no.3
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• pp.194-203
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• 1999

The axial stress in rock bolt, the shear stress at the bolt-grout interface and the neutral point are analyzed to understand the mechanical behavior of rook bolt. To analyze the support effects of rock bolt in various geological conditions, numerical analyses are performed with regard to bolt spacing and bolt length in several geological conditions and tunnel sizes. Through the numerical analyses, the distributions of maximum tensile stress and shear stress are determined. And the excavation width of underground opening affects the position of the neutral point. In the circular opening supported by pattern bolting, the increase of confining pressure, the reduction of plastic zone, and that of ground displacement are determined by using the radial stress increase ratio, the plastic zone reduction ratio and the displacement reduction ratio respectively. The results of this study can be applied to a practical tunnel design through understanding of the trends of these support effects.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.75-83
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• 2004

Ice rubble pieces broken by the bow impact load and side hull of an icebreaking vessel usually pass along the ship's bottom hull and may hit the propeller/rudder or other stern structures causing serious damage to ship's hull . Therefore it is important to estimate the size of broken ice pieces during the icebreaking process. The dynamic interaction process of icebreaker with infinite ice sheet is simplified as a wedge type beam of finite length supported by elastic foundation. The wedge type ice beam is leaded with vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum dynamic bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a failure length of broken ice sheet given design parameters. The results are compared to Nevel(1961)'s analytical solution for static load and observed pattern of ice sheet failure onboard an icebreaker. Also by comparing computed failure length with the characteristic length, the meaning of ice rubble sizes is discussed.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.661-667
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• 2002

Welding-induced buckling distortion is one of the most problematic concerns in both design and fabrication of welded thin-plate structures. This paper deals with experimental and numerical results of the welding-induced longitudinal and/or buckling distortion occurring in welding of 6mm-thick AH36 high strength steel plates. Effects of the heat input and the plate size on the distortion were experimentally evaluated for square plates. Bead-on-plate welding was performed with the submerged arc welding process along the middle line of plate specimens. Experimental results showed that the longitudinal distortion made a single curvature in the plate, and the distortion magnitude along the weld centerline was proportional to the heat input and the plate size. The experimental results were used to examine the validity of the numerical simulation procedure for welding-induced distortion where the longitudinal distortion mode and magnitude were numerically quantified. Three-dimensional, large deformation, welding simulations were performed for selected weld models. Numerical results of the distortion mode and magnitude were in a good agreement with experimental ones. Depending on the presence of halting the distortion growth during the cooling cycle of welding, the condition discriminating buckling distortion from longitudinal distortion was established. Eigenvalue analyses were performed to check the buckling instability of tested plates with different sizes subjected to different heat inputs. The perturbation load pattern for the analysis was extracted from longitudinal inherent strain distributions. Critical buckling curve from the eigenvalue analyses revealed that the buckling instability is manifested when plate size or heat input increases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.90-97
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• 2014

In this paper, we have designed the antenna for Korea SAT-5 Satellite Communication which can use Ka band in the earth station. The antenna structure consist of the the dual-offset gregorian reflector that has high gain and efficiency, the corrugated horn that has symmetric radiation patterns and low side lobe levels, the iris polarizer that make circular polarization and the OrthoMode Transducer that separate transmitting and receiving signals. The designed antenna gain is more than 45.7dBi in Tx-band which use LHCP and 42.0dBi in Rx-band which use RHCP. The co-polarized and cross-polarized radiation pattern comply with ITU-R S.580-6 and S.731-1 that are recommended by International Telecommunication Union in the geostationary satellite. The Axial ratio is less than 1.0dB in Tx-band and 1.5dB in Rx-band that meet MIL-STD-188-164A.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.956-962
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• 2005

This paper presents an integrated analysis of production and financing decisions. We assume that a cash storage unit is installed to manage the cash flows related with production activities such as raw material procurement, process operating setup, Inventory holding cost and finished product sales. Temporarily financial investments are allowed for more profit. The production plant is modeled by the Batch-Storage Network with Recycle Streams in Yi and Reklaitis (2003). The objective function of the optimization is minimizing the opportunity costs of annualized capital investment and cash/material inventory while maximizing stockholder's benefit. No depletion of all the material and cash storage units is major constraints of the optimization. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the cash and material inventory holdups. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two subproblems and analytical lot sizing equations under a mild assumption about the cash flow pattern of stockholder's dividend. The first subproblem is a separable concave minimization network flow problem whose solution yields the average material flow rates through the networks. The second subproblem determines the decisions about financial Investment. Finally, production and financial transaction lot sizes and startup times can be determined by analytical expressions as far as the average flow rates are calculated. The optimal production lot and storage sizes considering financial factors are smaller than those without such consideration. An illustrative example is presented to demonstrate the results obtainable using this approach.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.29-36
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• 2005

Many novel designs of planar antennas for related applications such as internal mobile phone antennas, base station antennas, WLAN or Bluetooth antennas, and so on, have been reported very recently, especially since the year 2000. In this thesis, Dualband internal antenna for GSM/DSC handset is proposed. The antenna has a size of about 38mm$\times$90mm$\times$1mm, giving a total mobile phone PCB for support and fold type Patch of about 30mm$\times$8mm$\times$3.2mm. This antenna characteristic facilitates the fine-tuning of the two operating frequencies of 909MHz and 1762MHz in this dualband design. The measured radiation pattern in the E-plane and H-plane for operating frequencies of 909MHz and 1762MHz is compared and analyzed. The designed and fabricated two band internal antenna for GSM/DSC handset have a gain between 0dBi and 2.0dBi at all bands.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.2
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• pp.83-90
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• 2000

In this paper, a stacked circular-disk microstrip 1${\times}$4 array antenna was designed and manufactured and tested to apply in next generation mobile communication, on IMT-2000 system(up-link: 1.885 GHz∼2.025 GHz, down-link: 2.11 GHz∼2.2 GHz) base station which has dual frequency, broadband and high-gain characteristics. The experimental results are as follows : resonant frequency of 1.885 GHz and 2.178 GHz VSWR (1.064 , 1.432), return loss (-30.19 dB , -24.99 dB), band width (VSWR<2) are 402 MHz, -3dB beam width at radiation pattern are ${\alpha}$E-16.8$^{\circ}$, ${\alpha}$H-69$^{\circ}$(1.885 GHz) and ${\alpha}$E-l5.2$^{\circ}$, ${\alpha}$H-51.5$^{\circ}$(2.178 GHz), gain(13.7 dBi∼15.21 dBi).

• The Journal of Information Systems
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• v.13 no.2
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• pp.225-240
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• 2004

The most critical problem of MIS evaluation is the lack of the systematic framework to cover various factors and viewpoints. To solve this problem, this study takes the multi-level and contingent approach to performance evaluation, composed of three levels: evaluating the contribution of MIS to an organization [strategy level]; evaluating the activities of MIS department or MIS function as an organizational sub-function through the overall MIS lifecycle [function level]; and evaluating the quality or productivity of the application systems as MIS outputs [system level]. Ideal MIS evaluation should include all three levels of the hierarchy with balanced importance. However, MIS evaluationcanbedividedintothreetypes,suchasstrategy-oriented, function-oriented and system-oriented evaluation, depending on the focus and emphasis of evaluation. The usage pattern of each evaluation type is analyzed according to contingent variables of MIS evaluation such as MIS maturity, information intensity and firm size, and top management's intent. It is also found that the firms of higher MIS maturity and top management's intent use the strategy-oriented evaluation type, and the firms with strategy-oriented evaluation type show a higher MIS performance. Further, MIS maturity and top management's intent show contingent effects between evaluation type and MIS performance. Some managerial implications can be drawn based on the results of the study. First, strategy-oriented evaluation of MIS is more important as many firms more often use information technology as a strategic weapon. Second, MIS performance varies with evaluation type. Therefore, the design of MIS evaluation framework should be done carefully in the strategic and managerial contexts. Third, firms are recommend to use a different evaluation type according to organizational characteristics such as MIS maturity and information intensity.