Improved channel assignment scheme with access control for thecommon packet channel in WCDMA systems

We propose a channel assignment scheme with access control for obtaining better system performance within the common packet channel (CPCH) access procedure of wideband code-division multiple-access (WCDMA) systems. The proposed scheme is analyzed taking multiple access interference into consideration and is compared with other schemes in the 3rd Generation Partnership Project (3GPP): the basic scheme, the channel monitoring scheme, and the channel assignment scheme without access control. The results show that the proposed scheme provides high throughput, even under high-loading conditions, since the access control algorithm based on channel load prohibits excessive interference     

A fault simulation method: Parallel pattern critical path tracing

We present a fast fault simulation algorithm for combinational circuits which combines parallel pattern evaluation and critical path tracing. When the number of faults is large, our algorithm exploits the full advantages of critical path tracing. As fault dropping progresses, the overhead for critical path tracing surpasses its advantages. On the other hand, the efficiency of Parallel Pattern Single Fault Propagation (PPSFP) increases rapidly since relatively few undetected faults remain, and they tend to be inactive. To avoid the overhead of critical path tracing and achieve the advantages of PPSFP, dynamic update of node classes is used to produce a smooth transition from critical path tracing to PPSFP. By using this approach, we get high performance for both small and large numbers of test patterns. Also, preprocessing related to structure analysis is avoided while achieving almost all of its advantages.This work was supported in part by National Science Foundation grant MIP-9003292.     

Evaluation of directivity for planar antenna arrays

In this paper, the directivity, including phase shift factors, for several types of uniformly excited planar arrays is obtained. Four types of dipole arrays are considered: arrays of collinear short dipoles, and of parallel short dipoles; and broadside and end-fire arrays of crosses of short dipoles. Curves of directivity versus inter-element spacing and scan angle for planar arrays with these element power patterns are presented     

Quantitative measurements of active and passive mechanical properties of adult cardiac myocytes

Cytoskeletal displacement, mechanical coupling between the cytoskeleton and the extracellular matrix, as well as nuclear mechanics can be independently quantified using novel methods based on high-resolution tracking of cellular structures and receptor bound magnetic beads in response to applied forces. These techniques can be applied to study the interaction between known protein function and specific changes in cellular mechanical properties and their role in cardiac hypertrophy.     

A New SOI LDMOSFET Structure with a Trench in the Drift Region for a PDP Scan Driver IC

To improve the characteristics of breakdown voltage and specific on‐resistance, we propose a new structure for a LDMOSFET for a PDP scan driver IC based on silicon‐on‐insulator with a trench under the gate in the drift region. The trench reduces the electric field at the silicon surface under the gate edge in the drift region when the concentration of the drift region is high, and thereby increases the breakdown voltage and reduces the specific on‐resistance. The breakdown voltage and the specific on‐resistance of the fabricated device is 352 V and 18.8 m·cm² with a threshold voltage of 1.0 V. The breakdown voltage of the device in the on‐state is over 200 V and the saturation current at V_gs=5 V and V_ds=20 V is 16 mA with a gate width of 150 µm.     

Infection of epithelial cells by pathogenic neisseriae reduces the levels of multiple lysosomal constituents

Members of our group reported recently that neisseria infection of human epithelial cells results in accelerated degradation of the major lysosomal integral membrane protein LAMP1 and that this is due to hydrolysis of this glycoprotein at its immunoglobulin A1 (IgA1)-like hinge by the neisseria type 2 IgA1 protease (L. Lin et al., Mol. Microbiol. 24:1083-1094, 1997). We also reported that the IgA1 protease plays a major role in the ability of the pathogenic neisseriae to survive within epithelial cells and hypothesized that this is due to alteration of lysosomes as a result of protease-mediated LAMP1 degradation. In this study, we tested the hypothesis that neisseria infection leads to multiple changes in lysosomes. Here, we report that neisseria infection also reduces the levels of three other lysosomal markers: LAMP2, lysosomal acid phosphatase (LAP), and CD63. In contrast, neither the epidermal growth factor receptor level nor the beta-tubulin level is affected. A detailed examination of LAMP2 indicated that the reduced LAMP2 levels are not the result of an altered biosynthetic rate or of cleavage by the IgA1 protease. Nevertheless, the protease plays a role in reducing LAMP2 and LAP activity levels, as these are partially restored in cells infected with an iga mutant. We conclude that neisseria infection results in multiple changes to the lysosomes of infected epithelial cells and that these changes are likely an indirect result of IgA1 protease-mediated cleavage of LAMP1.     

Simultaneous occurrence of hereditary angioneurotic edema and Crohn disease

Hereditary C1 esterase inhibitor deficiency is often associated with immunpathologic disorders. The authors present a case of the rare coincidence of hereditary angioedema (HAE) and Crohn's disease. The history of the patient is analysed along with the familial occurrence of the disease. Characteristic abdominal manifestations of C1 esterase inhibitor deficiency are compared to the clinical signs of Crohn's disease. Differential diagnostic pitfalls are described along with efficatious therapeutic options.     

DS/CDMA signature sequences based on PR-QMF banks

In this paper, we propose two classes of multivalued signature sequences for direct sequence code division multiple access (DS/CDMA) systems. The proposed classes are obtained from the coefficients of the subbands of perfect reconstruction quadrature mirror filterbanks (PR-QMF). The first and second classes are derived from the tree and lattice structure PR-QMF banks, respectively, and they both have perfect correlation properties for synchronous DS/CDMA systems. The second class, in addition, has generally better correlation properties than other well-known sequences in asynchronous DS/CDMA systems. Some numerical results for the performance of the asynchronous DS/CDMA systems with several sequences, including the second class of sequences, are obtained.     

Ultrasonic properties of fluorosilicate glass-ceramics at cryogenic temperatures

The longitudinal ultrasonic wave velocity and attenuation, and shear wave velocity for machinable fluorosilicate glass-ceramic (MACOR) samples (regular shelf stock, annealed to 900°C, and 1000°C for 10 hrs) were measured as the functions of frequency and temperature with the pulse-echo method. The frequency and temperature range used were 5 MHz to 50 MHz, and 100 K to 300 K respectively. Both velocities for three samples decrease linearly with temperature, and the ultrasonic attenuation increases linearly with the frequency square, and decreases monotonically with increasing temperature. These data were used to calculate the elastic moduli, Lame parameter, and Poisson's ratio for the materials.