• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.39-50
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• 2010

In this paper, we analyze and simulate the performance of a tactics mobile communication system based on ultra wide band (UWB) in multi-user interference (MUI) environments. This system adopts a double binary turbo code for forward error correction (FEC). Wireless channel is modeled a modified Saleh and Valenzuela (SV) model. We employ a space time block coding (STBC) scheme for enhancing system performance. System performance is evaluated in terms of bit error probability. From the simulation results, it is confirmed that the tactics mobile communication system based on UWB, which is encoded with the double binary turbo code, can achieve a remarkable coding gain with reasonable encoding and decoding complexity in multi-user interference environments. It is also known that the bit error probability performance of the tactics mobile communication system based on UWB can be substantially improved by increasing the number of iterations in the decoding process for a fixed cod rate. Besides, we can demonstrate that the double binary turbo coding scheme is very effective for increasing the number of simultaneous users for a given bit error probability requirement.

• Wind and Structures
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• v.13 no.1
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• pp.57-82
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• 2010

The 486m-long roof of Shenzhen Citizens Centre is one of the world's longest spatial lattice roof structures. A comprehensive numerical study of wind effects on the long-span structure is presented in this paper. The discretizing and synthesizing of random flow generation technique (DSRFG) recently proposed by two of the authors (Huang and Li 2008) was adopted to produce a spatially correlated turbulent inflow field for the simulation study. The distributions and characteristics of wind loads on the roof were numerically evaluated by Computational Fluid Dynamics (CFD) methods, in which Large Eddy Simulation (LES) and Reynolds Averaged Navier-Stokes Equations (RANS) Model were employed. The main objective of this study is to explore a useful approach for estimations of wind effects on complex curved roof by CFD techniques. In parallel with the numerical investigation, simultaneous pressure measurements on the entire roof were made in a boundary layer wind tunnel to determine mean, fluctuating and peak pressure coefficient distributions, and spectra, spatial correlation coefficients and probability characteristics of pressure fluctuations. Numerical results were then compared with these experimentally determined data for validating the numerical methods. The comparative study demonstrated that the LES integrated with the DSRFG technique could provide satisfactory prediction of wind effects on the long-span roof with complex shape, especially on separation zones along leading eaves where the worst negative wind-induced pressures commonly occur. The recommended LES and inflow turbulence generation technique as well as associated numerical treatments are useful for structural engineers to assess wind effects on a long-span roof at its design stage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.839-846
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• 1994

This paper presents a simultaneous solution algorithm for one-dimensional unsteady flow routing through a dendritic channel system. This simulations solution algorithm is based on the double-sweep method and utilizes separate recursion equations for continuity, momentum and energy equations for each of the individual components of a dendritic channel system. Through separate recursion equations for each of the components. the new algorithm converts a dendritic channel network problem into a single-channel problem. The new algorithm is utilized in conjunction with a linearized unsteady flow model using full dynamic flow equations. The required computer storage for the coefficient matrix of the whole system is reduced significantly from the $2N{\times}2N$ matrix to a $2N{\times}4$ matrix, where N is the number of cross sections used in the computation of flow variables in a dendritic channel system. The algorithm presented in this paper provides an efficient and accurate modeling of unsteady flow events through a dendritic channel system.

• The Korean Journal of Pain
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• v.28 no.2
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• pp.96-104
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• 2015

Background: The present experiment was conducted to identify the cooperative effect of serine histogranin (SHG) and noradrenaline in alleviating peripheral neuropathic pain. Methods: Chronic constriction injury of the right sciatic nerve was used to induce chronic neuropathic pain. For drug delivery, a PE10 tube was inserted into the subarachnoid space. Acetone drops and a $44^{\circ}C$ water bath were used to evaluate the cold and heat allodynia, respectively. Placing and grasping reflexes were used to assess the locomotor system. Results: SHG at 0.5 and $1{\mu}g$significantly (P < 0.05) decreased the thermal allodynia. The cold allodynia was also significantly reduced by intrathecal injections of 0.5 (P < 0.05) and $1{\mu}g$(P < 0.001) of SHG. $1{\mu}g$of noradrenaline, but not $0.5{\mu}g$, significantly alleviated the cold (P < 0.01) and thermal (P < 0.05) allodynia. The ameliorating effect of noradrenaline or SHG disappeared when the two compounds were administrated in equal concentrations. A significant difference (P < 0.01 in the acetone and P < 0.05 in the heat) was observed in the groups under equal doses of the two compounds, with a lower effectiveness of the combination therapy. Conclusions: Our findings suggest that the simultaneous administrations of noradrenaline and SHG do not result in synergistic analgesia, and combination therapy may not be a good approach to the treatment of chronic neuropathic pain syndrome.

• Korea and Global Affairs
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• v.2 no.2
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• pp.157-184
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• 2018

The study has applied the four stage "Model of State Behavior in Crisis" to trace the post 9/11 crisis foreign policy decision making process in Pakistan. It argues that ominous attacks on the United States by al-Qaeda and subsequent declaration of President Bush to fight against terrorism transformed the global and regional politico-security dimensions at t1 stage. Being a neighboring country, Pakistan's support was inevitable in the war on terror and Washington applied coercive diplomacy to win the cooperation from Islamabad. Consequently, in case of decline to accept American demands, Pakistan perceived threat to basic values/objectives of the country and simultaneous time pressure amplified the psychological stress in decision makers at t2 stage. Therefore, the decisional forum was setup at t3 stage and Pakistan decided to join the United States at t4 stage, which defused the foreign policy crisis.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.444-452
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• 2011

In this study the characteristics of natural ventilation of Venlo-type greenhouse with continuous roof vents were analyzed using commercial computational fluid dynamics (CFD) code. Developed CFD simulation model was verified by comparison with experimental data. Simulation errors were 1.9-46.0% for air velocity and 1.7-11.2% for air temperature at each measurement point. CFD simulations were conducted to estimate the effect of roof vents opening direction, opening angle, outside wind velocity and wind directions on ventilation rate and climate condition in greenhouse. The results of this study showed that ventilation rate of the present greenhouse was increased linearly in proportion to the increase of roof vent opening angle and outside wind velocity over 2.0 m/s. According to the analysis on the effects of different roof vent opening direction, simultaneous opening of wind and leeward vents showed the highest ventilation rate and lowest mean temperature in greenhouse.

• The Korean Journal of Pharmacology
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• v.12 no.1
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• pp.45-55
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• 1976

The effect of positive inotropic agents on the contractile properties of myocardial muscle were studied in the cat papillary muscle preparation. For the purpose, the effects of ouabain $(1{\times}10^{-6}g/ml)$, norepinephrine (0.05r/m1) and Aconiti tuber butanol fraction (AF(5), $1{\times}10^{-4}$, $5{\times}10^{-4}$, $1{\times}10^{-3}$, $2{\times}10^{-3}g/ml$) on the contractile dynamics of the papillary muscle preparation isolated from right ventricle of cat were observed in terms of the characteristics of isometric twitch and the lengh-tension relation, the force-velocity relation and the load-extension relation of the series elastic component of contractile model of A.V. Hill. All the studied inotropic drugs similary increased the rate and the intensity of the developed isometric tension, while shortened the time from onset of contraction to peak tension and the total duration of contraction. In the afterloaded simultaneous isotonic and isometric contraction, they also similary increased the maximal velocity of shortening accompanied with the increasing the maximum developed force. In the load-extension relation all the drugs, however, had no appreciable influence on the properties of the series elastic component. Increasing the concentration, Aconiti tuber butanol fraction produced more pronounced effect on all the studied parameters of isometric and isotonic contraction of cat papillary muscle preparation. From the aspect of contractile dynamics, it seemed that the positive inotropic effect of ouabain, norepinephrine and Aconiti tuber butanol fraction are similary achieved through an influence on the behavior of the contractile component only.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.7
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• pp.848-854
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• 2010

The objectives of this study were to estimate genetic parameters for the carcass price and carcass traits contributing to carcass grading and to investigate the influence of each carcass trait on the carcass price using multiple regression and path analyses. Data for carcass traits and carcass prices were collected from March 2003 to January 2009 on steers of Korean cattle raised at private farms. The analytical mixed animal model, including slaughter house-year-month combination, linear and quadratic slaughter age as fixed effects and random animal and residual effects, was used to estimate genetic parameters. The effects of carcass traits on the carcass price were evaluated by applying multiple regression analyses. Heritability estimates of carcass traits were $0.20{\pm}0.08$ for carcass weight (CWT), $0.33{\pm}0.10$ for back fat thickness (BFT), $0.07{\pm}0.05$ for eye-muscle area (EMA) and $0.25{\pm}0.10$ for marbling score (MS), and those of carcass prices were $0.21{\pm}0.10$ for auction price per 1 kg of carcass weight (AP) and $0.13{\pm}0.07$ for total price (CP). Genetic correlation coefficients of AP with CWT and MS were $-0.35{\pm}0.29$ and $0.99{\pm}0.04$, respectively, and those of CP with CWT and MS were $0.59{\pm}0.22$ and $0.39{\pm}0.29$ respectively. If an appropriate adjustment for temporal economic value is available, the moderate heritability estimates of AP and CP might suggest their potential use as the breeding objectives for improving the gross incomes of beef cattle farms. The large genetic correlation estimates of carcass price variables with CWT and MS implied that simultaneous selection for both CWT and MS would be also useful in enhancing income.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.9-18
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• 1994

The engineered safeguards of Wolsung nuclear power plant unit 1 contain redundant systems of 2-out-of-3 logic which are not operating under normal conditions but are called upon to act when emergency conditions develop. To ensure their operability, the systems are periodically tested. In this work, we develop the unavailability formulae for 2-out-of-3 logic configurations which take into account the failure probability of the channels tested due to human error in the simultaneous testing scheme. We also develop the model for the probability that the reactor is tripped during the surveillance test due to either system failure or human error. We determined the optimal inspection periods of safety systems, taking into account both the unavailability of the safety system and the probability that the reactor is tripped during the surveillance test. We compared the results with the inspection periods currently used at Wolsung NPP Unit 1. As a result, the inspection periods obtained using a minimum human error (8.24 $\times$ 1$^{-6}$ ) are shorter than those currently used in Wolsung NPP unit 1 whereas the inspection periods obtained using a maximum human error are (4.44 $\times$ 10$^{-4}$ ) longer than those used in Wolsung NPP unit 1.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.12
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• pp.1095-1100
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• 2007

Visibility of the satellite navigation is related to a environmental condition of a receiver. Obstacles like buildings and trees in urban areas can block signals and have effects on accuracy and reliability of positioning. This paper presents a method of creating 3D analysis model of urban canyon of Seoul using three-Dimensional digital map. Analysis techniques of visible satellites with Ray-Polygon Collision Detection and validation of algorithm through field tests are discussed. We have compared and analyzed the visibility of GPS and Galileo with respect to separate and simultaneous tracking in view of DOP (Dilution of Precision) using the 3D GIS digital map.