Estimation of continuous-time autoregressive model from finelysampled data

We extend our two earlier continuous-time estimation methods for continuous-time autoregressive (CAR) model to derive estimators using only finely sampled discrete-time data. The approach is based on the approximation of derivatives by divided differences, coupled with some bias correction. Two types of estimators are provided, having bias of the order O(h) or of O(h²) respectively, for small sampling interval h. The procedures are computationally efficient and always yield a stable autoregressive polynomial. Simulations show that their bias are quite low     

A dual-core 64-bit ultraSPARC microprocessor for dense server applications

A dual-core 64-bit microprocessor optimized for compute-dense systems such as rack-mount and blade servers for network computing was developed. The chip consists of two UltraSPARC II cores, each with its own 512 kB L2 cache, a DDR-1 memory controller, and symmetric multiprocessor bus (JBus) controllers. The 206-mm/sup 2/ die is fabricated in 0.13-/spl mu/m CMOS technology with seven layers of Cu and a low-k dielectric. The chip offers a highly efficient performance-per-watt ratio with a typical power dissipation of 23 W at 1.3 V and 1.2 GHz. A short design cycle was achieved by leveraging existing designs wherever possible and developing effective design methodologies and flows. Significant design challenges faced by this project are described. These include deep-submicron design issues, such as negative bias temperature instability (NBTI), leakage, coupling noise, intra-die process variation, and electromigration (EM). A second important design challenge was implementing a high-performance L2 cache subsystem with a short four-cycle core-to-L2 latency including ECC.     

COMPUTATION OF BEST BOUNDS OF PROBABILITIES FROM UNCERTAIN DATA

An uncertainty reasoning method is presented in this article. The method can be used to compute from a given set of conditional probabilities the best lower bounds and the best upper bounds of those conditional probabilities that are not explicitly provided. The computation of the best upper(lower) bound of such a conditional probability relies on solution of a linear programming problem. Some reduction techniques are proposed in this article to improve the efficiency of our uncertainty reasoning method. As illustrated in Section 4.3, for many uncertainty reasoning problems in medical diagnosis, by using our reduction techniques, the best range of a conditional probability, which is specified by a lower bound and an upper bound, can be computed in polynomial time in terms of the number of basic events involved in the reasoning.     

Automated multiple peptide synthesis: improvements in obtaining quality peptides

Production of multiple overlapping peptides is a key step in the identification of T-cell epitopes. A large number of peptides can be produced by using ABIMED's automated multiple peptide synthesizer. We report here considerable improvement in the software and chemistry of peptide synthesis by introducing a resin mixing step during coupling, when using this synthesizer. A comparison of two solvent systems for synthesis was performed. Six test peptides were synthesized by standard and modified methods. The purity of peptides, assessed by HPLC and mass spectrometry, showed a substantial improvement when automated resin mixing and mixed solvent system were used. These improvements enable us to produce 48 peptides within a week each of sufficient purity to be used for rapid screening of T-cell epitopes.     

A case study of geotextile-reinforced embankment on soft ground

Full-scale test embankments, with and without geotextile reinforcement, were constructed on soft Bangkok clay. The performances of these embankments are evaluated and compared with each other on the basis of field measurements and FEM analysis. The analyses of failure mechanisms and the investigations on the embankment stability using undrained conditions were also done to determine the critical embankment height and the corresponding geotextile strain. The high-strength geotextile can reduce the plastic deformation in the underlying foundation soil, increase the collapse height of the embankment on soft ground, and produce a two-step failure mechanism. In this case study, the critical strain in the geotextile corresponding to the primary failure of foundation soils may be taken as 2.5–3% irrespective of the geotextile reinforcement stiffness.     

HgCdTe focal plane arrays for dual-color mid- and long-wavelength infrared detection

Raytheon Vision Systems (RVS, Goleta, CA) in collaboration with HRL Laboratories (Malibu, CA) is contributing to the maturation and manufacturing readiness of third-generation, dual-color, HgCdTe infrared staring focal plane arrays (FPAs). This paper will highlight data from the routine growth and fabrication of 256×256 30-μm unit-cell staring FPAs that provide dual-color detection in the mid-wavelength infrared (MWIR) and long wavelength infrared (LWIR) spectral regions. The FPAs configured for MWIR/MWIR, MWIR/LWIR, and LWIR/LWIR detection are used for target identification, signature recognition, and clutter rejection in a wide variety of space and ground-based applications. Optimized triple-layer heterojunction (TLHJ) device designs and molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all dual-color FPA configurations exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art, single-color technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An FPA architecture based on a single-mesa, single-indium bump, and sequential-mode operation leverages current single-color processes in production while also providing compatibility with existing second-generation technologies.     

Noise reduction in sputtered W/GaAs Schottky junctions

The noise characteristics of sputtered W/GaAs Schottky diodes, annealed at temperatures up to 700°C, have been investigated. A useful figure of merit for such millimeter and submillimeter mixer diodes is the noise performance at an RF where accurate measurements are available. Noise temperatures measured at a typical mixer intermediate frequency of 4GHz under DC biased conditions have been reduced significantly by rapid thermal annealing. The best noise data have been obtained with an annealing time of 2 minutes at 600°C and are consistent with good mixer performance.     

A study of heat transfer in a circulating fluidized bed

An experimental investigation was carried out to study the effects of operating parameters on the local bed-to-wall heat transfer coefficient in a 4.5 m tall, 0.150 m diameter circulating fluidized bed with a bed temperature in the range of 65°C to 80°C, riser flow rate varying from 1400 litres/min to 2000 litres/min, bed inventory in the range of 15 kg to 25 kg of sand, and average sand sizes of 200 μm, 400 μm and 500 μm. A heat flux probe was attached to the riser wall at five different vertical locations for measuring the heat flux from the bed to the wall surface. From the present work, the heat transfer coefficient in the dilute phase was found to be in the range of 62 to 83 W/m²K, 51 to 74 W/m²K, and 50 to 59 W/m² K for sand sizes of 200 μm, 400 μm and 500 μm, respectively. Relevant mathematical correlations were developed to predict local heat transfer coefficient based on the results of the practical work.     

Subchronic MK-801 treatment to juvenile rats attenuates environmental effects on adult spatial learning

Forty eight primary and 20 secondary chondrosarcomas were treated surgically 1975 through 1991. An evaluation of the data of the Bone Tumor Register of the Semmelweis Medical University proved that the incidence of the malignant transformation and development of secondary chondrosarcomas is 3% and 2.6% among solitary osteochondromas. The authors summarize the clinicopathological characteristics of the malignant transformation. A retrospective evaluation of the histological grade of the malignancy proved that 67% of tumors were classified as grade I; 18% as grade II and 15% as grade III. The survival of the patients was mainly determined by the grade of the malignancy. A 95% 5-years survival was found in the grade I group and a 10% survival only in the grade II and III groups. In the cases of highly malignant chondrosarcomas radical surgical intervention i.e. amputation is recommended, considering the most often extra-compartmental location of the tumors. Low malignant and intra-compartmental highly malignant chondrosarcomas should be treated, however, by limb saving surgery. In the cases of large inresecable but low malignant chondrosarcomas debulking surgery is also acceptable.