• Journal of KIISE
• /
• v.42 no.6
• /
• pp.707-712
• /
• 2015

Mobile cloud computing is a technology that uses cloud services to overcome resource constrains of a mobile device, and it applies the computation offloading scheme to transfer a portion of a task which should be executed from a mobile device to the cloud. If the communication cost of the computation offloading is less than the computation cost of a mobile device, the mobile device commits a certain task to the cloud. The previous cost analysis models, which were used for separating functions running on a mobile device and functions transferring to the cloud, only considered the amount of data transfer and response time as the offloading cost. In this paper, we proposed a new task partitioning scheme that considers the frequency of function calls and data synchronization, during the cost estimation of the computation offloading. We also verified the energy efficiency of the proposed scheme by using experimental results.

• Atmosphere
• /
• v.20 no.4
• /
• pp.451-466
• /
• 2010

This edition has continued since 2006 tropical cyclone season our effort to provide standard tropical cyclone summaries by the western North Pacific basin and detailed reviews of operationally or meteorologically significant tropical cyclones to document significant challenges and shortfalls in the tropical cyclone warning system to serve as a focal point for research and development efforts. The tropical cyclone season of 2009 in the western North Pacific basin is summarized and the main characteristics of general atmospheric circulation are described. Also, the official track and intensity forecasts of these cyclones are verified. The total number is less than 59-year (1951~2009) average frequency of 26.4. The 2009 western North Pacific season was an inactive one, in which 22 tropical storms generated. Of these, 13 TCs reached typhoon (TY) intensity, while the rest 9 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - three STS and six TS storms. On average of 22 TCs in 2009, the Korea Meteorological Administration official track forecast error for 48 hours was 219 km. There was a big challenge for individual cyclones such as 0902 CHAN-HOM, 0909 ETAU, and 0920 LUPIT resulting in significant forecast error, with both intricate tracks and irregular moving speed. There was no tropical cyclone causing significant direct impact to the country. The tropical cyclone season in 2009 began in May with the formation of KUJIRA (0901). In September and October, ten TSs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to July. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2009 summertime. Year 2009 has continued the below normal condition since mid 1990s which is apparent in the decadal variability in TC activity.

• The Journal of Korean Medicine
• /
• v.37 no.1
• /
• pp.10-20
• /
• 2016

Objectives: Poncirus trifoliata Rafinesque has been known to have anti-allergic effects in skin diseases. However, anti-atopic dermatitis effects of P. trifoliata Rafinesque have not been studied yet in skin diseases. The present study evaluated the anti-atopic dermatitis effects of P. trifoliata Rafinesque (PTR) using external treatments on AD. Methods: AD lesions were induced by the repeated application of 2, 4-Dinitrochlorobenzene (DNCB) on the shaved back of BALB/c mice. $100{\mu}{\ell}$ of PTR extracts was applied to the AD lesions for 11 days. Histological assessments, mast cells count and serum levels of IgE were analyzed. The anti-pruritic effects of PTR were examined by the change of scratching frequency and nerve growth factor (NGF) expression. In addition, the anti-inflammatory effects of PTR were examined by the expressions of Th2/Th1 cytokines and pro-inflammatory in dorsal skin. Results: Histopathological findings showed that topical application of PTR decreased the thickness of dermal and epidermal skin compared with the DNCB group. PTR also notably decreased the mast cells count and serum IgE. The scratching behavior of mice and expression of NGF were significantly reduced. In addition, PTR group significantly suppressed the IL-4, IL-6, IFN-${\gamma}$ and TNF-${\alpha}$ cytokines compared to the DNCB group. Conclusions: These results indicated that P. trifoliata Rafinesque possess anti-pruritus and anti-atopic dermatitis properties. Therefore, P. trifoliata Rafinesque might be used for treatment of pruritus and atopic dermatitis.

• Korea-Australia Rheology Journal
• /
• v.14 no.1
• /
• pp.33-45
• /
• 2002

Recent results obtained for the port-pom model and the constitutive equations with time-strain separability are examined. The time-strain separability in viscoelastic systems Is not a rule derived from fundamental principles but merely a hypothesis based on experimental phenomena, stress relaxation at long times. The violation of separability in the short-time response just after a step strain is also well understood (Archer, 1999). In constitutive modeling, time-strain separability has been extensively employed because of its theoretical simplicity and practical convenience. Here we present a simple analysis that verifies this hypothesis inevitably incurs mathematical inconsistency in the viewpoint of stability. Employing an asymptotic analysis, we show that both differential and integral constitutive equations based on time-strain separability are either Hadamard-type unstable or dissipative unstable. The conclusion drawn in this study is shown to be applicable to the Doi-Edwards model (with independent alignment approximation). Hence, the Hadamardtype instability of the Doi-Edwards model results from the time-strain separability in its formulation, and its remedy may lie in the transition mechanism from Rouse to reptational relaxation supposed by Doi and Edwards. Recently in order to describe the complex rheological behavior of polymer melts with long side branches like low density polyethylene, new constitutive equations called the port-pom equations have been derived in the integral/differential form and also in the simplifled differential type by McLeish and carson on the basis of the reptation dynamics with simplifled branch structure taken into account. In this study mathematical stability analysis under short and high frequency wave disturbances has been performed for these constitutive equations. It is proved that the differential model is globally Hadamard stable, and the integral model seems stable, as long as the orientation tensor remains positive definite or the smooth strain history in the flow is previously given. However cautious attention has to be paid when one employs the simplified version of the constitutive equations without arm withdrawal, since neglecting the arm withdrawal immediately yields Hadamard instability. In the flow regime of creep shear flow where the applied constant shear stress exceeds the maximum achievable value in the steady flow curves, the constitutive equations exhibit severe instability that the solution possesses strong discontinuity at the moment of change of chain dynamics mechanisms.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.860-863
• /
• 1992

In this paper, we investigate $\pi$-A isotherms of biological lipid layer such as cholesterol and phosphatidyl choline to study a gas sensor characteristics which response only to specific materials. And, we also deposit it on the surface of quartz crystal by vertical dipping method and horizontal lifting method. Then, we evaluate the deposition status of cholesterol and phosphatidyl choline LB film using AT-cut quartz crystal. We obtain the following results: (1) Cholesterol's solid surface pressure is about 20$\sim$40(dyne/cm) and limiting area is about 50${\AA}^2$/molecule. And, phosphatidyl choline's surface pressure is about 25$\sim$40(dyne/cm) and limiting area is about 20 ${\AA}^2$/molecule. (2) When LB films are deposited, the deposition ratio is coincident with the frequency shift. Therefore, we can evaluate the deposition status of LB film. (3) For cholesterol, Y type LB films are deposited up to 15 layers by vertical dipping method. (4) For phosphatidyl choline, X typo LB films are deposited to 15 layers by horizontal lifting method. But, in case of vertical dipping method, the deposition status is not good.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.3
• /
• pp.211-216
• /
• 2015

Large hydraulic excavator weighted 90 tons used the several pumps installed in parallel to use the hydraulic pump driving gearbox to improve fuel consumption by improving the energy efficiency of the hydraulic system. Gearbox connected to hydraulic pump supply the mechanical output to the high pressure and low pressure pump to be supplied by torque and rotation, which are the mechanical power, through a input shaft connected to large size engine of the excavator. So, gearbox connected to hydraulic pump is same as main artery in the human body and is required long life because it operates the hydraulic pump continuously during operating the engine. This study had used oil contamination analysis method to check the wear characteristics of the gearbox and frequency response characteristic analysis method to check the failure of the teeth failures of gearbox, while the test equipment adopted by the electrical feedback method to reduce the energy consumption was operating for the life assessment, in which the required power was 600 kW input power.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.10
• /
• pp.1125-1131
• /
• 2014

This work presents a vulnerability assessment procedure for a complex structure using vibration characteristics. The structural behavior of a three-dimensional framed structure subjected to impact forces was predicted using the spectral element method. The Timoshenko beam function was applied to simulate the impact wave propagations induced by a high-velocity projectile at relatively high frequencies. The interactions at the joints were analyzed for both flexural and longitudinal wave propagations. Simulations of the impact energy transfer through the entire structure were performed using the transient displacement and acceleration responses obtained from the frequency analysis. The kill probabilities of the crucial components for an operating system were calculated as a function of the predicted acceleration amplitudes according to the acceptable vibration levels. Following the proposed vulnerability assessment procedure, the vulnerable positions of a three-dimensional combat vehicle with high possibilities of damage generation of components by impact loading were identified from the estimated vibration responses.

• Journal of Plant Biotechnology
• /
• v.31 no.1
• /
• pp.25-29
• /
• 2004

To establish the system of in uitro plant regeneration, the leaf segments of Sedum sarmentosum were cultured on MS media supplemented with different levels of 2,4-D, NAA and BA. The callus induction and growth showed a good response on MS medium supplemented with 3.0mg/L 2,4-D and 1.0mg/L BA, but a few callus induced on medium containing NAA and BA. In plant regeneration, combination of BA and NAA promoted shoot organogenesis from callus, and the highest frequency was obtained on MS medium supplemented with 0.2mg/L NAA and 3.0mg/L BA. When calli were transferred to the plant regeneration medium containing 0.2mg/L NAA and 3.0mg/L BA, healthy shoots without hyperhydricity were continuously induced (17.2 plantlets per callus) after 50 days of culture. When regenerated plantlets were transferred onto hormone-free MS medium, rooting was easily achieved from all of them.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.12
• /
• pp.1243-1249
• /
• 2012

Finite element models are updated in two stages in this paper. In the first stage, damping is neglected, and mass and stiffness matrices of a finite element model are updated using an optimization technique. The objective function for optimization consists of natural frequencies and mode shapes obtained from experimental modal testing data and finite element analysis. In the second stage, damping is considered with the mass and stiffness matrices fixed. A damping matrix is estimated assuming a proportional damping system. Then the damping matrix is adjusted using an optimization process so that the difference between the analytical and measured frequency response functions becomes minimum. This procedure of model updating has been applied to a simulated system and an experimental cantilever beam.

• Journal of the Korean Society of School Health
• /
• v.15 no.2
• /
• pp.233-248
• /
• 2002

Purpose : Sexual abuse especially in younger group have been growing. This study was performed to propose the fundamental data for developing early education program to prevent damage from sexual harassment in elementary school students. Method : Questionnaire survey on cognitions and experiences about sexual harassment was done on 3125 elementary school students from seven elementary schools in Busan area from January to March, 2002. Data analysis was done with SPSS (ver 10.0). Results : Though 82% of the students have ever herd about sexual harassment previously, but self assessment of 'well-known' was only 5%. About 40% of them have ever experienced audio-visual sexual materials mainly through PC (18%), media (14%), etc. And, 60% of them have ever educated about sexual harassment. In cognitions, they agreed 'unwanted touch', 'intentional showing his (her) own body', 'send lewd mails and pictures', but disagreed 'ask massage from aged', 'gaudy joke' as one of sexual harassment. In attitudes, 'no response', 'defense with friends and family', 'express unpleasantness apparently' were desirable pattern, instead, 'his (her) own responsibility', 'problem only between person concerned', 'neglect is the best way' were undesirable. About 24% of them have ever experienced at least one of the fifteen types of sexual harassment with major types of lewd mails pictures (11%), hugging (5%), ask massage (4.7%) and unwanted touch (3.3%). The experience by gender was higher in girls (25.0%) than boys (22.4%) with no statistical significance. The mean level of cognition and attitude out of one hundred was $70.3{\pm}28.1$ and $73.5{\pm}15.9$, respectively. The mean frequency of experience was $0.4{\pm}1.1$ times. The level of cognition and attitude was higher in girls, 6th graders, and in ever educated group (p<0.001). Conclusions : The cognition level of elementary school students about sexual harassment assessed considerable. And, they also experienced several types of sexual harassment, though not too much. Therefore, compatible education program let them able to protect themselves from sexual harassment should be developed and applied even in early school age.