Method for Veterbi decoding of large constraint length convolutional codes

A new method of Viterbi decoding of convolutional codes lends itself to a pipline VLSI architecture using a single sequential processor to compute the path metrics in the Viterbi trellis. An array method is used to store the path information for NK intervals where N is a number, and K is constraint length. The selected path at the end of each NK interval is then selected from the last entry in the array. A trace-back method is used for returning to the beginning of the selected path back, i.e., to the first time unit of the interval NK to read out the stored branch metrics of the selected path which correspond to the message bits. The decoding decision made in this way is no longer maximum likelihood, but can be almost as good, provided that constraint length K in not too small. The advantage is that for a long message, it is not necessary to provide a large memory to store the trellis derived information until the end of the message to select the path that is to be decoded; the selection is made at the end of every NK time unit, thus decoding a long message in successive blocks

Adaptive Cache-Oblivious All-to-All Operation

Modern processors rely on cache memories to reduce the latency of data accesses. Extensive cache misses would thus compromise the usefulness of the scheme. Cache-aware algorithms make use of the knowledge about the cache, such as the cache line size, L, and cache size, Z, to be cache efficient. However, careful tuning of these parameters for these algorithms is needed for different hardware platforms. Cache-oblivious (CO) algorithms were first introduced by Leiserson to work without the knowledge of the cache parameters mentioned earlier, but still achieve optimal work complexity and optimal cache complexity. Here we present CO algorithms for all-to-all operations (analogous to the cross-product operation). Its applications include Convolution, Polynomial Arithmetic, Multiple Sequence Alignment, N-Body Simulation, etc. Given two lists each with n elements, a naive implementation of all-to-all operation incurs O(n²/L) cache misses. Our CO version incurs only O(n²/L²√Z) cache misses. Preliminary experiments on Opteron 1.4GHz and MIPS 250MHz show that the CO implementation achieves two times faster. The profiling tool further confirms that the amount of cache misses is significantly lower. We also consider various situations where (a) the elements have non-uniform sizes, (b) an element cannot fit into the cache, (c) the lengths of the lists vary, and (d) an element is linked list. In addition, we study the extension to K-lists All-to-All Operation and its application. Finally, we will present the empirical results and compare with cache-aware algorithms.Singapore-MIT Alliance (SMA

Gamma-Ray Sterilization Effects in Silica Nanoparticles/γ-APTES Nanocomposite-Based pH-Sensitive Polysilicon Wire Sensors

In this paper, we report the γ-ray sterilization effects in pH-sensitive polysilicon wire (PSW) sensors using a mixture of 3-aminopropyltriethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs) as a sensing membrane. pH analyses showed that the γ-ray irradiation-induced sensitivity degradation of the PSW pH sensor covered with γ-APTES/silica NPs nanocomposite (γ-APTES+NPs) could be restored to a condition even better than prior to γ-ray irradiation by 40-min of post-sterilization room-temperature UV annealing. We found that the trapping charges caused by γ-ray sterilization primarily concentrated in the native oxide layer for the pH sensor covered with γ-APTES, but accumulated in the γ-APTES+NPs layer for the γ-APTES+NPs-covered sensor. It is believed that mixing the PDMS-treated silica NPs into γ-APTES provides many γ-APTES/SiO2 interfaces for the accumulation of trapping charges and for post-sterilization UV oxidation, thus restoring γ-ray-induced sensor degradation. The PDMS-treated silica NPs not only enhance the sensitivity of the pH-sensitive PSW sensors but are also able to withstand the two-step sterilization resulting from γ-ray and UV irradiations. This investigation suggests γ-ray irradiation could be used as a highly-efficient sterilization method for γ-APTES-based pH-sensitive biosensors

The interaction between paternalistic leadership and achievement goals in predicting athletes’ sportspersonship

Paternalistic leadership, which is a prevalent leadership style in business contexts in non-Western cultures, is characterized by three dimensions: authoritarianism, benevolence, and morality. The current study of 252 Taiwanese intercollegiate athletes (Mage=20.91 years) explored this leadership style in a sports setting and examined the extent to which the interaction of paternalistic leadership and achievement goals predicted athletes’ sportspersonship. Participants completed the Paternalistic Leadership in Sport Questionnaire, Task and Ego Orientation in Sport Questionnaire, and Multidimensional Sportspersonship Orientation Scale. Athletes’ ego-orientation and perceived authoritarian leadership were related to lower levels of sportspersonship. In contrast, task-orientation, benevolent leadership, and moral leadership predicted higher levels of sportspersonship and confirmed findings reported in the research literature. Hierarchical regression analyses revealed that authoritarianism moderated the relationship between ego, orientation and sportspersonship. Future sports research should consider paternalistic leadership as an alternative approach when investigating coach-athlete relationships and the influence of coaches’ leadership on athletes’ growth and moral responses