Low-power data-dependent 8/spl times/8 DCT/IDCT for video compression

Traditional fast discrete cosine transform (DCT)/inverse DCT (IDCT) algorithms have focused on reducing arithmetic complexity and have fixed run-time complexities regardless of the input. Recently, data-dependent signal processing has been applied to the DCT/IDCT. These algorithms have variable run-time complexities. A two-dimensional 8/spl times/8 low-power DCT/IDCT design is implemented using VHDL by applying the data-dependent signal processing concept onto the traditional fixed-complexity fast DCT/IDCT algorithm. To reduce power, the design is based on Loeffler's fast algorithm, which uses a low number of multiplications. On top of that, zero bypassing, data segmentation, input truncation and hardwired canonical sign-digit (CSD) multipliers are used to reduce the run-time computation, hence reducing the switching activities and the power. When synthesised using CMC 0.18 /spl mu/m 1.6 V CMOSP technology, the proposed FDCT/IDCT design consumes 8.94/9.54 mW, respectively, with a clock frequency of 40 MHz and a processing rate of 320 Msample/s. This design features lower dynamic power consumption per sample, i.e. it is more power-efficient than other previously reported high-performance FDCT/IDCT designs.     

A solution to the stacking sequence of a composite laminate plate with constant thickness using simulated annealing algorithms

Due to its high reliability, composite material is commonly used in industry. Moreover, the stacking sequence is very crucial to the strength of the composite material. However, the arrangement of this sequence is very time-consuming. Actually, since stacking sequences are usually NP complete, simulated annealing (SA) algorithms were borrowed to deal with the stacking sequence problems in this study. The edging stress of a composite plate with constant thickness, which was obtained using an analytical method, was used as the objective function in the SA algorithms. Three examples of constant thickness and symmetrical composite laminate plates were used to examine the performance of the proposed algorithms. The results of computational tests presented are very promising.     

Effect of gender and left ventricular dysfunction on the incidence of hypotension induced by dobutamine stress echocardiography

BACKGROUND: Of patients who undergo dobutamine stress echocardiography (DSE), 14% to 38% experience hypotension that sometimes requires termination of the test before an adequate cardiac work-load is reached. The mechanisms of hypotension reportedly are related to peripheral vasodilation, a decrease in cardiac output, and left ventricular (LV) cavity obliteration. DSE is performed increasingly in women and in patients with LV dysfunction. However, the impact of gender and LV dysfunction on DSE-induced hypotension has not been elucidated. METHODS AND RESULTS: Clinical, hemodynamic, and echocardiographic characteristics were studied in 412 patients undergoing DSE, 82 patients with an LV ejection fraction of 40% or less, and 147 women. Hypotension, defined as a decrease in systolic blood pressure of at least 20 mm Hg, occurred in 117 (28%) patients. Hypotension was more common in women than men (36% vs 24%, P = .01). Hypotension was also more common in older adults (P = .004), persons taking diuretics (P = .025) or angiotensin-converting enzyme inhibitors (P = .01), and persons with higher baseline blood pressures (P < .0001). Hypotension was not related to the use of beta blockers, calcium channel blockers, digoxin, nitrates, LV dimensions, or ejection fraction. CONCLUSIONS: The incidence of DSE-induced hypotension is related to gender but not to the level of LV systolic function. It also is associated significantly with higher age, and use of angiotensin-converting enzyme inhibitors or diuretics.     

A WIP-based exception-management model for integrated circuit back-end production processes

Meeting due dates for delivery of products is a key factor in achieving customer satisfaction in today’s globally competitive semiconductor market. However, undesirable production variations are inevitable in this industry, especially for ‘back-end’ factories that are closer to customers. This makes it difficult for management to maintain (or improve) a factory’s performance with respect to delivery on due dates. In practice, production managers ameliorate the adverse effects of manufacturing uncertainties by control of work in progress (WIP). The present study therefore proposes a WIP-exception management model to define, detect, and respond to WIP exceptions. First, a model for determining acceptable WIP deviation levels (AWDLs) is established to assist production managers in identifying WIP exceptions on monitored workstations. A correction mechanism is then proposed to adjust deviations in WIP levels (‘WIP exceptions’) in accordance with the projected AWDLs as soon as possible. A simulation model is constructed, and experiments are then conducted to evaluate the proposed model. The proposed model is confirmed as being able to set appropriate and effective WIP-exception conditions to trigger correction actions. The simulation experiment also demonstrates that the WIP-correction action can shorten the ‘back-to-normal’ duration, prolong the time between successive WIP exceptions, and improve average on-time delivery percentage. The study concludes that the proposed model does determine effective exception-triggering conditions, rectifies abnormal WIP levels promptly, and results in improved performance on due-date delivery for semiconductor ‘back-end’ factories.     

Nasopharyngeal Castleman's disease

A 19-year-old male was admitted to our clinic because of nasal obstruction and intermittent postnasal drip of 3 to 4 years' duration. Physical examination revealed a wide-based, smooth-surfaced nasopharyngeal tumor which was suspected to be a nasopharyngeal angiofibroma after examination of computed tomographic scans and an angiogram. However, after the tumor was removed by surgical excision via a transpalatal approach, the pathologic examination revealed Castleman's disease of the hyaline-vascular type. There was neither evidence of recurrence nor nasal problems at 4 years' follow-up. To our knowledge, Castleman's disease, or angiofollicular lymph node hyperplasia, may present as a local or generalized tumor-like condition, usually in the chest or abdomen, and may involve both the lymph nodes and non-nodal tissues. A review of previous articles reveals that there has not been any report of Castleman's disease found in the nasopharynx. This rare disorder is presented and discussed.     

Analysis of microwave MESFET power amplifiers for digital wireless communications systems

The analysis of microwave MESFET power amplifiers (PAs) for digital wireless communications by using the hybrid Volterra-series method is presented in this paper. Compared with the traditional approach in the pure frequency-domain operation, the hybrid method has the advantage of fast computation for the continuous spectral signals with the same accuracy. The major modification is the equivalent baseband formulations in the time domain for the digital modulation signal, and the frequency-domain treatment with the nonlinear system via Volterra-series expansion. The MESFET two-dimensional current model is utilized and detailed current expressions are given to account for the gate-drain cross-term effects, while the nonlinear capacitors are also considered to describe the MESFET nonlinear characteristics completely. Circuit-level simulation yields the output modulation signal parameters with the measured data confirmation. System performance degradations due to nonlinear distortions of the MESFET PA are also performed for the communication link with the additive white Gaussian noise channel model. These results would be very useful in PA designs for digital wireless communications systems.     

Primary lymphoreticular tumors of the orbit

Primary orbital lymphomas are rare. We report nine such cases (4 with DWDL, 3 with DPDL, 1 with DHL and 1 unclassifiable lymphoma). All patients achieved clinical complete remission (CR). Of those who completed treatment more than a year ago, three continue to be in CR at 17, 24 & 25 months and two are lost to follow up.     

A 40-mW 55 Mb/s CMOS equalizer for use in magnetic storage readchannels

A monolithic active equalizer in 2-μm CMOS technology is described, suitable for use in magnetic storage read channels employing peak-detection. Computer simulation of the channel and numerical optimization of equalizer performance have led to a 4-pole equalizer which outperforms conventional 7-pole linear-phase pulse-slimming equalizers. Circuits with matched and scaled stray capacitances use low transconductance amplifiers, with a total on-chip power dissipation of 40 mW (excluding output buffers). A master-slave architecture tunes filter pole frequencies and quality factors (Q) to their nominal values against process and temperature variations