Journalists’ Evaluation of the South Korean Government's Crisis Management in the Cheonan Incident

The purpose of this study was to examine how journalists judge and react to the withholding of information by the government during a national crisis. This article analyses the case of the sinking of the Cheonan, which killed four South Korean marines and sparked extreme tension throughout the Korean peninsula. For this research, in‐depth interviews were conducted with journalists who reported on the Cheonan incident. All participants (11 journalists) believed that the South Korean government withheld information about the cause of the Cheonan sinking for a period of time. Half of the journalists did not agree with the governmental restrictive information policy, while the other half accepted this as the government acting in the best interest of national security in a crisis situation.     

Development of lipase inhibitors from various derivatives of monascus pigment produced by Monascus fermentation

Derivatives of monascus pigment having high lipase-inhibitory activities were developed and characterized. Various derivatives of monascus pigment were produced during Monascus fermentation with added l-, d-amino acids. From them, compounds having high inhibitory activities against a porcine pancreatic lipase were selected. Monascus pigments produced with aromatic and non-polar aliphatic l-, d-amino acids revealed strong inhibitory activities against the lipase. l-Trp and d-Tyr derivatives showed especially low IC₅₀ values of 61.2 and 103 μM, respectively. Further structure modifications of pigment derivatives were made with amino acid esters and dipeptides for enhanced inhibitory activity. l-Leu-OEt and l-Tyr-OEt derivatives made via further structure modifications showed high lipase-inhibitory activities with IC₅₀ values of 12.2 and 13.8 μM, respectively. The l-Leu-OEt derivative exhibited some specificity against porcine pancreatic lipase but not exhibit high activities against other digestive enzymes. Some compounds were developed from modification of monascus pigment followed by lipase-inhibitory activity tests.     

An approach to multi-criteria assembly sequence planning using genetic algorithms

This paper focuses on multi-criteria assembly sequence planning (ASP) known as a large-scale, time-consuming combinatorial problem. Although the ASP problem has been tackled via a variety of optimization techniques, these techniques are often inefficient when applied to larger-scale problems. Genetic algorithm (GA) is the most widely known type of evolutionary computation method, incorporating biological concepts into analytical studies of systems. In this research, an approach is proposed to optimize multi-criteria ASP based on GA. A precedence matrix is proposed to determine feasible assembly sequences that satisfy precedence constraints. A numerical example is presented to demonstrate the performance of the proposed algorithm. The results of comparison in the provided experiment show that the developed algorithm is an efficient approach to solve the ASP problem and can be suitably applied to any kind of ASP with large numbers of components and multi-objective functions.     

Measurement uncertainties arising from unpowered shipment of dcvoltage references

We have measured the hysteresis in output voltage arising from loss of power for three Fluke 732B dc voltage references. Continuously powering the internal temperature-controlled oven provides the best accuracy with such Zener-diode-based dc voltage references. Batteries are used to provide power continuity when shipping between laboratories. We have shown that for these particular instruments, an apparent hysteresis induced by humidity is likely to dominate any hysteresis arising from loss of battery power when transit between laboratories takes three days or more. Our conclusion is that as much, if not more, care needs to be taken when dealing with humidity than with loss of battery power when shipping between laboratories. When the highest accuracy of dc voltage comparison is required, it becomes necessary to apply voltage corrections using the measured values of humidity coefficients and the relative humidity occurring during transit     

Design of holographic polymer‐dispersed liquid crystals based on solubility parameters

BACKGROUND: A slight change of polymer structure leads to a significantly different solubility parameter (SP), which is related to incompatibility and interface anchoring energy between a polymer and a liquid crystal (LC). RESULTS: Holographic gratings in polymer‐dispersed liquid crystals have been fabricated based on various urethane acrylate oligomer sizes and type of reactive diluent at two LC loadings. A large SP gap, using N‐vinylpyrrolidone as reactive diluent, gave much faster saturation of diffraction efficiency at higher level, but the grating failed to operate. On the contrary, films having a small SP gap, using 2‐ethylhexyl acrylate, operated under 20 V with a response time of about 10 ms, although their saturation of diffraction efficiency was relatively low. The results were interpreted in terms of morphology (determined using scanning electron microscopy), anchoring energy and resin elasticity. CONCLUSION: Low driving voltage and high diffraction efficiency are obtained by controlling the SP gap between LC and polymer. Copyright © 2007 Society of Chemical Industry     

Prediction of the melt flow index using partial least squares and support vector regression in high-density polyethylene (HDPE) process

In polyolefin processes the melt flow index (MFI) is the most important control variable indicating product quality. Because of the difficulty in the on-line measurement of MFI, a large number of MFI estimation and correlation methods have been proposed. In this work, mechanical predicting methods such as partial least squares (PLS) method and support vector regression (SVR) method are employed in contrast to conventional dynamic prediction schemes. Results of predictions are compared with other prediction results obtained from various dynamic prediction schemes to evaluate predicting performance. Hourly MFIs are predicted and compared with operation data for the high density polyethylene process involving frequent grade changes. We can see that PLS and SVR exhibit excellent predicting performance even for severe operating situations accompanying frequent grade changes.     

Direct numerical simulation of flow characteristics and heat transfer enhancement in a rib-dimpled cooling channel

The present study reports the numerical investigation on the flow characteristics and heat transfer enhancement of the rib-dimpled channels. Two geometric variables were considered: the rib angle, θ, and the length between the rib center and the dimple rim, l. Nine cases were investigated by combining three different rib angles with three different lengths. Direct numerical simulations were conducted with a Reynolds number of 2800. As θ and l changed, the flow characteristics of the rib-dimpled channel were altered, which lead to different characteristics in the flow mixing and heat transfer rate. The span-wise rotating flow and the up-wash counter rotating vortices played an important role in the augmentation of heat transfer rate. The rib-dimpled channel with l = 0.15 and θ = 70° showed the maximum increase of 32 % in the volume goodness factor, in comparison with the general dimpled channel.

     

Design and control of an ethyl acetate process: coupled reactor/column configuration

In this paper, design and control of a realistic coupled reactor/column process to produce ethyl acetate is studied. The process design is more complicated because the ethyl acetate product is neither the lightest nor the heaviest component in the system. A search procedure is proposed to obtain the optimum process design and operating condition of this process. The optimum process design is the one that minimize the Total Annual Cost (TAC) of this process while satisfying the stringent product impurity specifications. The optimum overall process design includes a continuous-stirred tank reactor (CSTR) coupled with a rectifier, a decanter, another stripper, and a recycle stream. After the process design is established, the next step is to use dynamic simulation to test the appropriate control strategy for this process. Sensitivity analysis is performed to obtain the suitable temperature control points for the columns. The proposed control strategy is very simple containing only one temperature control loop in each column. This recommended simpler control strategy uses the ratio of acetic acid feed rate to ethanol feed rate to control the 5th stage temperature of the rectifier and uses the stripper reboiler duty to control the 5th stage temperature of the stripper. The proposed control strategy does not need any on-line composition measurements and can properly hold product purity in spite of feed flow rate and feed composition disturbances. For small deviations of the product impurity compositions during disturbances, a slow cascade outer composition loop structure can be implemented using off-line composition measurements from the quality lab.     

Long‐term memory colors of Korean and Hungarian observers

Long‐term memory colors have been discussed extensively in the literature but previous articles focused on reflecting color samples. In this work, we studied six important long‐term memory colors, skin (both Caucasian and Oriental), green grass, blue sky, deciduous foliage, orange, and banana, in the viewing situation of a self‐luminous color monitor, for two different observer groups, Koreans and Hungarians. We quantified the long‐term memory colors of both observer groups in terms of CIE L*,a*,b* values, in a given viewing situation, and estimated interobserver variability. We used a comprehensive psychophysical experimental methodology including both the method of constant stimuli and the method of adjustment. In many cases, we found significant differences (t tests, P < 0.05) between the Korean and the Hungarian long‐term memory colors. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 176–183, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20192     

用于锁模光纤激光陀螺的相敏检测

通过采用锁相放大器,演示了一种性能明显提高的锁模光纤激光陀螺.结果表明锁相放大器的输出与转动速率之间具有理想的线性关系,并对两脉冲(在时间间隔测量过程中引起相位误差)之间的光强差不敏感.与以往报道的时间间隔测量相比,演示了长期稳定性提高了二个数量级.