Frame synchronization word in W-CDMA system

This letter presents a set of sequences of length 15 called frame synchronization words in wideband code-division multiple-access (W-CDMA) system. They all have two-valued ideal auto-correlation property. And the correlation function between a preferred pair of sequences shows also two-valued cross-correlation property with minus peak at the middle shift and lowest out-of-phase cross-correlation value of 1. Since the length of the sequences is equal to the number of slots per frame, they are suitable for slot-by-slot and double-check frame synchronization confirmation. We discuss the realization circuit for the generation of frame synchronization words by using the concept of preferred pairs of frame synchronization words, complementary mapping relationship, and maximal length sequence.     

Contents of Volume 22 (2002)

Volume Contents

Contents of Volume 22 (2002)     

Improved Ge Surface Passivation With Ultrathin SiOX Enabling High-Mobility Surface Channel pMOSFETs Featuring a HfSiO/WN Gate Stack

To realize high-mobility surface channel pMOSFETs on Ge, a 1.6-nm-thick SiO_X passivation layer between the bulk Ge substrate and HfSiO gate dielectric was introduced. This approach provides a simple alternative to epitaxial Si deposition followed by selective oxidation and leads to one of the highest peak hole mobilities reported for unstrained surface channel pMOSFETs on Ge: 332 cm² middotV^-1middots^-1 at 0.05 MV/cm-a 2times enhancement over the universal Si/SiO₂ mobility. The devices show well-behaved output and transfer characteristics, an equivalent oxide thickness of 1.85 nm and an I_ON/I_OFF ratio of 3times10³ without detectable fast transient charging. The high hole mobility of these devices is attributed to adequate passivation of the Ge surface     

采用轻压下技术减少板坯中心偏析

近来,为提高竞争力,提高API钢市场占有率,必须增加高质量API钢的产量,尽最大努力去满足消费者对产品质量的严格要求,尤其是生产耐酸钢.不仅要最大限度地控制钢中残留元素和夹杂物的含量,而且还要避免中心偏析.因此,POSCO正致力于开发生产工艺,更新基础设备,以满足消费者的要求.在POSCO的Gwangyang工厂,由于受铸机条件限制,控制板坯中心偏析有一定难度.为了克服这一困难,Gwangyang工厂在1-3铸机上安装了动态轻压下设备.动态轻压下系统的操作条件处于优化阶段.轻压下设备上采用了动态二次冷却系统和热示踪模型,板坯中心偏析系数有了明显降低.     

Development of integrated automatic diagnosis method for loose parts monitoring system

Generally, it is known that loose parts in the reactor coolant systems (RCS) bring serious damage into the system components and impede the normal function of the system. So, it is necessary to rapidly respond when the impact event has occurred. This paper presents a realization of automatic diagnosis algorithm for LPMS (Loose Parts Monitoring System) and application results to the impact test data at YongGwang Nuclear Power Plant Unit 3 (YGN3), Kori Nuclear Power Plant Unit 4 (KNU4) and the real data at YongGwang Nuclear Power Plant Unit 1 (YGN1). The integrated diagnosis algorithm is composed of three parts; prefiltering, impact location and mass estimation. The prefiltering is needed to reject low frequency background noises. To estimate the impact location, the starting points of impact are detected from the filtered signals and compared to produce the time differences, and then the modified triangular method is applied. To estimate the mass and energy of a loose part, we automatically compute the maximum amplitude and the initial half period. Additionally, a modified impact theory considering amplitude and energy attenuation effects is applied.

To show the effectiveness of the proposed diagnostic method, the real impact test data at YGN3, KNU4 and the real impact data at YGN 1 is used. The analysis results show that the location estimation error is on average below 7.5%, and the average mass estimation is within 40%.     

Hot carrier degradation of HfSiON gate dielectrics with TiN electrode

Hot carrier reliability of the HfSiON dielectric with the TiN metal gate electrode has been studied in the nMOS and pMOS short channel transistors. Hot carrier induced degradation of the high-/spl kappa/ gate stack devices are severe than the one in the SiO/sub 2//poly devices. It is determined that total threshold voltage shift during a hot carrier stress is a sum of contributions from both hot carrier and cold carrier effects. The hot carrier contribution induces permanent damage while cold carrier contribution is shown to be reversible. The contribution from the cold carrier can be evaluated by applying a de-trapping (opposite polarity) bias after the stress.     

Short-term load forecasting for the holidays using fuzzy linear regression method

Average load forecasting errors for the holidays are much higher than those for weekdays. So far, many studies on the short-term load forecasting have been made to improve the prediction accuracy using various methods such as deterministic, stochastic, artificial neural net (ANN) and neural network-fuzzy methods. In order to reduce the load forecasting error of the 24 hourly loads for the holidays, the concept of fuzzy regression analysis is employed in the short-term load forecasting problem. According to the historical load data, the same type of holiday showed a similar trend of load profile as in previous years. The fuzzy linear regression model is made from the load data of the previous three years and the coefficients of the model are found by solving the mixed linear programming problem. The proposed algorithm shows good accuracy, and the average maximum percentage error is 3.57% in the load forecasting of the holidays for the years of 1996-1997.     

Novel zero-voltage and zero-current-switching full-bridge PWMconverter using a simple auxiliary circuit

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulsewidth modulation converter is presented to simplify the circuits of the previously presented ZVSCS converters. A simple auxiliary circuit, which consists of one small capacitor and two small diodes, is added in the secondary to provide ZVZCS conditions to primary switches, as well as to clamp secondary rectifier voltage. The additional clamp circuit for the secondary rectifier is not necessary. The auxiliary circuit includes neither lossy components nor additional active switches, which makes the proposed converter efficient and cost effective. The principle of operation, features, and design considerations are illustrated and verified on a 2.5 kW 100 kHz insulated-gate-bipolar-transistor-based experimental circuit     

Evaluation of handheld products by computing user hand fatigue

In this study, we propose a method to evaluate handheld devices at the design stage. Many researchers have carried out highly reliable evaluations of the comfort level in grasping motions. Nevertheless, the presently available product evaluation criteria based on finger movement are still unsatisfactory. Accordingly, this study proposes a new concept called angle-based fatigue (ABF), which can use finger movements to evaluate the fatigue felt by the user at the product design stage. The proposed method is expected to maximize efficiency at the product design stage because it can easily and rapidly calculate the degree of fatigue experienced by a user when using a particular design.