A Novel Data Transmission Scheme for ATSC Terrestrial DTV Systems

In Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) systems, additional very low‐rate data can be transmitted by modulating the amplitude and polarity of the transmitter identification (TxID) signal. Although the additional data transmission scheme offers reliable transmission and has a very large coverage area, it has a limitation on the data rate. In this paper, we propose a novel additional data transmission scheme based on the TxID sequences of the ATSC DTV system and Walsh modulation. The proposed scheme not only increases the data rate significantly, but also offers a virtually identical coverage area compared to a conventional scheme.     

QoS‐aware routing and power control algorithm for multimedia service over multi‐hop mobile ad hoc network

This paper presents a QoS (quality of service) aware routing and power control algorithm consuming low transmission power for multimedia service over mobile ad hoc network. Generally, multimedia services need stringent QoS over the network. However, it is not easy to guarantee the QoS over mobile ad hoc network since its network resources are very limited and time‐varying. Furthermore, only a limited amount of power is available at mobile nodes, which makes the problem more challenging. We propose an effective routing and power control algorithm for multimedia services that satisfies end‐to‐end delay constraint with low transmission power consumption. The proposed algorithm supports the required bandwidth by controlling each link channel quality over route in a tolerable range. In addition, a simple but effective route maintenance mechanism is implemented to avoid link failures that may significantly degrade streaming video quality. Finally, performance comparison with existing algorithms is presented in respect to traditional routing performance metrics, and an achievable video quality comparison is provided to demonstrate the superiority of the proposed algorithm for multimedia services over mobile ad hoc network. Copyright © 2010 John Wiley & Sons, Ltd.     

An experimental study on semiconductor process chiller using the digital scroll compressor

This study is about the application of a digital scroll compressor in order to save the energy of a semiconductor process chiller. This study conducted experiments to find characteristics related to the application of a digital scroll compressor to the semiconductor process chiller. In this study, temperature rise and fall experiments designed for rapid response to temperature change and control precision experiments per temperature range depending on the load change were carried out, and then, operational characteristics of each control method were compared with those of the old model. The power consumption and time in the case of temperature rise were 8.36 kW and about 38 min., respectively. The power consumption and time in the case of temperature fall were 5.25 kW and about 27 min., respectively. With regards to control precision based on the bypass of the digital scroll compressor, as the by-pass amount increased, the power consumption of the compressor became less, but the set temperature control was between ±0.1°C and ±0.4°C. As a result of comparing the old model and new model in terms of control precision, the old model’s precision was ±1.5°C and the new model’s precision was ±0.1°C when the temperature was set at 0°C. In addition, with the set temperature of 20°C, the precision of the old model declined to ±1.0°C while the precision of the new model increased to ±0.2°C. It was found that the set temperature increases with a decrease in the power consumption. This study demonstrates that the application of a digital scroll compressor to a semiconductor process chiller is effective, not only in saving energy, but also with improving control precision.     

Effects of milling on aromatics,lipophilic phytonutrients,and fatty acids in unprocessed white rice of scented rice ‘Cheonjihyang-1-se<Emphasis Type="Bold">’</Emphasis>

To understand effects of milling, scented rice ‘Cheonjihyang-1-se’ was milled from 10 to 140 s and changes in volatiles, phytonutrients, and fatty acids were evaluated. Among 43 identified odor-active compounds, four volatiles, including hexan-3-one, exhibited decreases of up to 78%, while four others including (E)-non-2-enal, increased following milling. Levels of 2-acetyl-1-pyrroline, the most distinctive popcorn-flavoring compound in scented rice, were not affected by the degree of milling (DM). Partial least squares discriminant analyses of volatiles were able to differentiate white rice according to the DM. Benzene and 2-pentylfuran showed the highest variable importance in projection scores, which could be applied in estimating the DM of rice. Milling significantly decreased tocopherols, tocotrienols, squalene, phytosterols contents and oleic acid composition, while palmitic acid composition was increased. These results suggest milling-dependent variations in phytonutrient levels and lipid composition, as well as changes in aroma and subsequent market quality, in ‘Cheonjihyang-1-se’ rice.     

Evaluation of In vitro antioxidant properties of roasted hulled barley (Hordeum vulgare L.)

The antioxidant properties of roasted hulled barley (Hordeum vulgare L.) were tested using in vitro assays, including the total phenolic content (TPC), total flavonoid content (TFC), and DPPH, ABTS, and ferric reducing antioxidant power (FRAP) assays. Hulled barley was roasted at 0, 170, 210, and 250°C for 20 min. The effects of the aqueous heating time at 100°C from 0 to 60 min and the blending ratio of barley and water from 1:2 to 1:5 in aqueous solutions were evaluated. p-Coumaric and ferulic acid contents were analyzed. The highest antioxidant activities were observed in 250°C roasted samples, although the p-coumaric and ferulic acid contents were high at 210°C. The highest antioxidant capacity in aqueous solution was observed at 60 min of extraction and in samples with a 1:2 blending ratio.     

Effect of pH on non-enzymatic browning reaction during γ-irradiation processing using sugar and sugar–glycine solutions

Effects of pH on the non-enzymatic browning reaction caused by γ-irradiation processing were investigated. The brown colour development of irradiated sugar–glycine solutions was greater in a buffer system than in deionized distilled water (DDW) with higher pH. Although browning of irradiated sugar solution without glycine was highly increased was in alkaline buffer, no browning was developed in DDW. The maximum browning of the solutions of sugar and sugar–glycine were observed at pH 10 and pH 8, respectively. The browning intensity was in the following order: sucrose ? fructose > glucose. Non-constant pH was observed in DDW (dropped pH between 1.58 and 2.03 units); however, the use of buffers was partially effective in keeping pH constant (pH dropped between 0.03 and 0.56 units). When the irradiated solutions of sugar with and without glycine were analyzed using reverse phase high performance liquid chromatography with diode-array detection (HPLC-DAD), three peaks were separated at 3.37 ± 0.04, 4.60 ± 0.02, and 2.53 ± 0.26 min, and the λ_max values of these peaks were the range 259–288 nm. The sum of the areas of these peaks at 260 nm increased with increasing pH. The results of this study indicated that conditions of the system, such as pH and media, can influence the non-enzymatic browning reaction during γ-irradiation.     

Transverse Dispersion Caused by Secondary Flow in Curved Channels

A new theoretical equation is proposed to describe the streamwise variations of the transverse velocity along a curved channel with a constant curvature. Furthermore, based on this theoretical equation for the transverse velocity, a new equation for the transverse dispersion coefficient is developed to incorporate the effect of the secondary flow on the transverse dispersion in curved channels. The new equations for the transverse velocity and dispersion coefficient are verified with experimental data sets that were obtained from laboratory experiments conducted in two different channels. The results show that the proposed velocity equation properly describes the streamwise variations of the secondary flow developed in the curved channels. The reach-averaged values of the transverse dispersion coefficient calculated by the new equation are in relatively good agreement with the observed values from the laboratory channels. Sensitivity analysis reveals that both the secondary flow and the transverse dispersion coefficient are proportional to the roughness factor, and in inverse proportion to the aspect ratio of the channel.