• Journal of Intelligence and Information Systems
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• v.15 no.3
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• pp.81-102
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• 2009

In this study, we investigated how to achieve differentiation for the ISM (Internet Shopping Mall) to improve profitability, which is required for survival in the fiercely competitive ISM industry. We analyzed implementation level key managerial factors that could contribute to the differentiation of the ISM. The research model is constructed through integration of two distinctive research streams of e-commerce. The one is B2C differentiation strategy research, most of which are conceptual and conducted at a strategy level, and the other is empirical research analyzing the antecedents of customer satisfaction at the ISM. This study is organized as follows. First, we draw upon transaction cost theory to organize constructs representing customer value associated with the customer buying decision process. Next, after reviewing comprehensive managerial factors that could impact on customer value, we selected 15 managerial factors that could contribute to the differentiation of the ISM to deliver value to customers. Finally, the resulting structural model is validated through empirical analyses. The results provide insights for future studies on ISM differentiation.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.305-314
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• 1996

In the paper, we divide the ATM cells generated by multimedia systems that want to transmit multimedia informations over B-ISDN into two categories:i)a media cell with a media information and ii) a synchronization cell with a synchronization information. We induce a media cell loss equation and a synchroni- zation cell loss equation based on probability distribution functions with on-off source as an input traffic model. In order to meet the requirements of real-time and integrity of multimedia informations, multimedia synchronization cells should provide the delay-sensitive and the loss-sensitive requirements. A traffic control mechanism needs to satisfy above requirements. According to the performance evaluation by a traffic control model simulation, we describe both spatial priority for minimizing the synchronization cell loss and temporal priority for reducing the synchronization cell delay must be applied simultaneously.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.59-70
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• 2003

Proposed CCRSVP (Candidate Casting RSVP) algorithm is a new fast handoff method which uses advanced multicasting method and RSVP for IEEE 802.11 Wireless LAN (WLAN) environments. The proposed algorithm shows good performance in the handoff latency and the B/W efficiency aspect and guarantees QoS because it uses L2 information (BSSID) of WLAN and starts to reserve resources and multicast packets before L2 handoff completes. We also propose a Markov chain performance analysis model in which we can analyze the handoff performance of various handoff algorithms. Using the model, we compare bandwidth efficiency of the proposed algorithm with existing handoff algorithms which use RSVP by analyzing blocking probability of session, resource usage, and the average number of ongoing session in a cell. The results show that the proposed algorithm shows better performance than the existing algorithms in the above three performance aspects.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.578-586
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• 2002

Flow structures around a rectangular prism have been investigated by using a PIV(Particle Image Velocimetry) technique. A thick turbulent boundary layer was generated by using spires arid roughness elements. The boundary layer thickness, displacement thickness and momentum thickness were 650mm, 117.4mm and 78mm, respectively. The ratio between the model height(40mm) and the boundary layer thickness H/$\delta$, was 0.06. The Reynolds number based on the free stream velocity and the height of the model was 7.9$\times$10$^3$. The PIV measurements were performed at three different wall normal planes. Three recirculation regions at forward facing step, top of the roof and backward facing step are clearly seen and show three dimensional features. Dramatic changes of flow patterns are observed in the wake regions in the different spanwise wall normal planes. Instead of reattachment and recirculation zone, rising streamlines are depicted at the normal planes near the side wall due to the interaction with a rising horse shoe vortex. The peak of turbulent kinetic energy occurs at the separation bubble on top of the roof and the magnitude is 2.5 times higher compared with that of the wake region.

• The Journal of Korean Society of Virology
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• v.28 no.1
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• pp.63-69
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• 1998

To establish in vivo antiviral evaluation system by using murine herpesvirus intracerebral infection model, 5-6 female BALB/c mice per group aged 5 weeks were inoculated i.c. into cerebrum with different inocular HSV-1 F. Signs of clinical disease noted everyday for one month. Observed were body weight decrease, neurological signs and death caused by encephalitis. Mice discontinued body weight decrease were recovered from the disease, and keratitis was often observed during recovery. The groups inoculated with higher than 1,000 PFU showed 100% mortaltiy and $LD_{50}$ was <100 PFU/mouse. To study the effect of virus inoculum sizes on antiviral effect of acyclovir (ACV), mice inoculated with different inocula were administered i.p. with different doses of ACV immediately after infection, and twice a day for 5 days. The higher inculum size, the less protective. $ED_{50}$ of ACV was >25, >25, 18.4 and 8.0 mg/kg b.i.d. in the group infected with 1,000,000, 100,000, 10,000 and 1,000 PFU/mouse, respectively. $LD_{50}$ of ACV was 62.5 mg/kg b.i.d. Therapeutic index of ACV was <2.5, <2.5, 3.0 and 7.0 in the groups with inocula 1,000,000, 100,000, 10,000 and 1,000 PFU/mouse, respectively. Inoculum size 1,000 PFU/mouse showing 100% mortaltiy and 5-6 days mean time to death, 5 days drug administration and 14 days observation will be future experimental conditions.

• CELLMED
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• v.10 no.3
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• pp.25.1-25.7
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• 2020

Allergic Rhinitis (AR) is an IgE (immunoglobin-E) mediated inflammatory condition of upper respiratory tract; main clinical features involve runny nose, sneezing, nasal obstruction, itching and watery eyes. AR is a global problem and has large variations in incidences, currently affects up to 20% - 40% of the population worldwide. It may not be a life-threatening disease per se but indisposition from the condition can be severe and has the potential to adversely affect the daily functioning of life. Classical yoga literature indicates that, components of yoga have been used to treat numerous inflammatory conditions including upper respiratory tract. A few yoga intervention studies reported improvement in lung capacity, Nasal air flow and symptoms of allergic rhinitis. This review examined various anti-inflammatory pathways mediated through Yoga that include downregulation of pro-inflammatory cytokines and upregulation of anti-inflammatory cytokines. The hypothalaminic-pitutary-adrenal (HPA) axis and vagal efferent stimulation has been reported to mediate anti-inflammatory effect. A significant reduction is also reported in other inflammatory biomarkers like- TNF-alpha, nuclear factor kappa B (NF-κB), plasma CRP and Cortisol level. Neti, a yogic nasal cleansing technique, reported beneficial effect on AR by direct physical cleansing of thick mucus, allergens, and inflammatory mediator from nasal mucosa resulting in improved ciliary beat frequency. We do not find any study showing effect of yoga on neurogenic inflammation. In summary, Integrated Yoga Therapy may have beneficial effect in reducing symptoms and improving quality of life for patients with allergic rhinitis. Yoga may reduce inflammation through mediating neuro-endocrino-immunological network. Future studies are needed to explore the mechanism how yoga might modulate immune inflammation cascade and neurogenic inflammation at the cellular level in relevance to allergic rhinitis; the effects of kriyas (yogic cleansing techniques) also need to be evaluated in early and late phase of AR. So the proposed model could guide future research.

• Tunnel and Underground Space
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• v.11 no.3
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• pp.217-224
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• 2001

Rock masses are usually discontinuous in nature due to various geological processes and contain rock joints and bridges. Crack propagation and coalescence processes in rock bridge mainly cause rock failures in slopes, foundations, and tunnels. In this study, we focused on the crack initiation, propagation and coalescence process of rock materials containing two pre-existing open cracks arranged in different geometries. Specimens of 120${\times}$60${\times}$25 mm in size, which were made of Yeoman Marble, were prepared. In the specimens, two artificial cracks were cut with pre-existing crack angle ${\alpha}$, bridge angle ${\beta}$, pre-existing crack length 2c and bridge length 2b. Wing crack initiation stress, wing crack propagation angle, and crack coalescence stress were measured and crack initiation, propagation and coalescence processes were observed during uniaxial compression. Crack coalescence types were classified and analytical study using Ashby and Hallam model (1986) was performed to be compared with the experimental results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.4
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• pp.151-164
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• 1998

Changes in tides and tidal currents in Chonsu Bay caused by the construction of Seosan A and B reclamation regions have been investigated using a depth-integrated two-dimensional tidal model. Three water level recorders were deployed for about one month and used for the specification of the open boundary condition. The computed currents were found to be in a good agreement with the measurements at two stations within Chonsu Bay. Comparison of the absolute velocities computed with the conditions before and after the embankment clearly shows that the reduction in tidal current amplitude is evident throughout the bay and the magnitude of the reduction increases to the north. Calculation shows that the embankment has advanced the time of drying at the northern part of the bay by about 51 minutes and has increased the exposure time by about 23 minutes. The high water time has advanced by about 1 hour, lowering the high water level by about 15 cm.

• Korean Journal of Acupuncture
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• v.22 no.3
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• pp.165-174
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• 2005

Objective : The objective of this study is to investigate the inhibitor effects of an traditional oriental herb, Sophora flavescens on the hepatic and renal side effects of chemotherapy by using B16-BL6 melanoma-injected C57BL6 mouse tumor model. Methods : In this study, the effects of an traditional oriental herb, Sophora flavescens, on the side effects of chemotherapy were studied using B16 melanoma-injected C57BL6 mouse tumor model. Results : Sophora flavescen has significant effect on the reduction of the side effects of chemotherapy. Sophora flavescen recovered the reduction of WBC and RBC during cisplatin chemotherapy. Water extract of Sophora flavescens significantly inhibited cisplatin-induced increase of serum blood urea nitrogen (BUN) which is a good indicator of renal toxicity. Sophora flavescens extract does not decrease the anti-tumor activity of cisplatin showing that it can selectively inhibit side effects of anticancer drugs preserving beneficial effort. Conclusion : Theses results suggest a possibility that Sophora flavescens extract can be used for cancer patients for the reduction of the side effects and improving the quality of life during chemotherapy of cancer patients.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.925-931
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• 2010

The paper describes a Large Eddy Simulation (LES) study of turbulent flow around a cavity. A series of three-dimensional cavities placed in a turbulent boundary layer are simulated at a Reynolds number of $1.0{\times}10^5$ by considering U and h, which represent the velocity at the top and the depth of the cavity, respectively. In order to obtain the appropriate solution for the filtered Navier-Stokes equation for incompressible flow, the computational mesh forms dense close to the wall of the cavity but relatively coarse away from the wall; this helps reduce computation cost and ensure rapid convergence. The Boussinesq hypothesis is employed in the subgrid-scale turbulence model. In order to determine the subgrid-scale turbulent viscosity, the Smagorinsky-Lilly SGS model is applied and the CFL number for time marching is set as 1.0. The results show the flow variations inside cavities of different sizes and shapes.