The novel free-form deformation (FFD) technique presented in the paper uses scalar fields defined by skeletons with arbitrary topology. The technique embeds objects into the scalar field by assigning a field value to each point of the objects. When the space of the skeleton is changed, the distribution of the scalar field changes accordingly, which implicitly defines a deformation of the space. The generality of skeletons assures that the technique can freely define deformable regions to produce a broader range of shape deformations.

There have been numerous attempts recently to promote technology based education (Shrestha, 1997) in the poorer third world countries, but so far all these have not provided a sustainable solution as they are either centered and controlled from abroad and relying solely on foreign donors for their sustenance or they are not web-based, which make distribution problematic, and some are not affordable by most of the local population in these places. In this paper we discuss an application, the Local College Learning Management System (LoColms), which we are developing, that is both sustainable and economical to suit the situation in these countries. The application is a web-based system, and aims at improving the traditional form of education by empowering the local universities. Its economicability comes from the fact that it is supported by traditional communication technology, the public switching telephone network system, PSTN, which eliminates the need for packet switched or dedicated private virtual networks (PVN) usually required in similar situations. At a later stage, we shall incorporate ontology and paging tools to improve resource sharability and storage optimization in the Proxy Caches (ProCa) and LoColms servers. The system is based on the client/server paradigm and its infrastructure consists of the PSTN, ProCa, with the learning centers accessing the universities by means of point-to-point protocol (PPP).

This paper presents an efficient way to preserve the volume of implicit surfaces generated by skeletons. Recursive subdivision is used to efficiently calculate the volume. The criterion for subdivision is obtained by using the property of density functions and treating different types of skeletons respectively to get accurate minimum and maximum distances from a cube to a skeleton. Compared with the criterion generated by other ways such as using traditional Interval Analysis, Affine Arithmetic, or Lipschitz condition, our approach is much better both in speed and accuracy.

As a variant of process algebra, π-calculus can describe the interactions between evolving processes. By modeling activity as a process interacting with other processes through ports, this paper presents a new approach: representing workflow models using π-calculus. As a result, the model can characterize the dynamic behaviors of the workflow process in terms of the LTS (Labeled Transition Semantics) semantics of π-calculus. The main advantage of the workflow model\'s formal semantic is that it allows for verification of the model\'s properties, such as deadlock-free and normal termination. Moreover, the equivalence of workflow models can be checked through weak bisimulation theorem in the π-calculus, thus facilitating the optimization of business processes.

The closed-loop stability issue of finite-precision realizations was investigated for digital controllers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resulting from using finite word length (FWL) block-floating-point representation scheme. A block-floating-point FWL closed-loop stability measure was derived which considers both the dynamic range and precision. To facilitate the design of optimal finite-precision controller realizations, a computationally tractable block-floating-point FWL closed-loop stability measure was then introduced and the method of computing the value of this measure for a given controller realization was developed. The optimal controller realization is defined as the solution that maximizes the corresponding measure, and a numerical optimization approach was adopted to solve the resulting optimal realization problem. A numerical example was used to illustrate the design procedure and to compare the optimal controller realization with the initial realization.

Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge\'s dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters\' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters.

Some characteristics of the electricity load and prices are studied, and the relationship between electricity prices and gas (fuel) prices is analyzed in this paper. Because electricity prices are strongly dependent on load and gas prices, the authors constructed a model for electricity prices based on the effects of these two factors; and used the Geometric Mean Reversion Brownian Motion (GMRBM) model to describe the electricity load process, and a Geometric Brownian Motion (GBM) model to describe the gas prices; deduced the price stochastic process model based on the above load model and gas price model. This paper also presents methods for parameters estimation, and proposes some methods to solve the model.

In routine design of tensioned membrane st ructures, the membrane is gen erally modeled using space membrane elements and the cables by space cable eleme nts, with no sliding allowed between the membrane and the cables. On the other h and, large deflections are expected and sliding between the membrane and the cab les is inevitable. In the present paper, the general finite element code ABAQUS was employed to investigate the influence of cable sliding on membrane surface o n the structural behavior. Three analysis models were devised to fulfill this pu rpose: (1) The membrane element shares nodes with the cable element; (2) The cab le can slide on the membrane surface freely (without friction) and (3) The cable can slide on the membrane surface, but with friction between the cable and the membrane. The sliding problem is modeled using a surface-based contact algorithm. The results from three analysis models are compared, showing that cable slidin g has only little influence on the structure shape and on the stress distributio ns in the membrane. The main influence of cable sliding may be its effect on the dynamic behavior of tensioned membrane structures.

Pile drivability is a key problem during the stage of design and construction installation of pile foundations. The solution to the one dimensional wave equation was used to determine the impact force at the top of a concrete pile for a given ram mass, cushion stiffness, and pile impedance. The kinematic equation of pile toe was established and solved based on wave equation theory. The movements of the pile top and pile toe were presented, which clearly showed the dynamic displacement, including rebound and penetration of pile top and toe. A parametric study was made with a full range of practical values of ram weight, cushion stiffness, dropheight, and pile impedance. Suggestions for optimizing the parameters were also presented. Comparisons between the results obtained by the present solution and in-situ measurements indicated the reliability and validity of the method.

Biot\'s two-phase theory for fluid-saturated porous media was applied in a study carried out to investigate the influence of water saturation on propagation of elastic wave in transversely isotropic nearly saturated soil. The characteristic equations for wave propagation were derived and solved analytically. The results showed that there are four waves: the first and second quasi-longitudinal waves (QP1 and QP2), the quasi-transverse wave (QSV) and the anti-plane transverse wave (SH). Numerical results are given to illustrate the influence of saturation on the velocity, dispersion and attenuation of the four body waves. Some typical numerical results are discussed and plotted. The results can be meaningful for soil dynamics and earthquake engineering.

In this paper, the Life Cycle of Urban Development was firstly analyzed, and the phases of Life Cycle Assessment applied to Urban Development (ULCA) were described. As a case study, ULCA was applied in the environmental impact assessment of the land readjustment project of Hyogo District of Saga, Japan. In addition, mitigation proposals for reducing CO₂ were also presented and the relevant environmental effects were simulated.

In this paper based on the experiment principle of evaluating adhesion property by scratch testing, the peeling mechanism of thin films is discussed by applying contact theory and surface physics theory. A mathematical model predicting the critical load is proposed for calculating critical load as determined by scratch testing. The factors for correctly evaluating adhesion of coatings according to the experimental data are discussed.

Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifica tion of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-ch a in acyl-derivative of epigallocatechin-3-o-gallate (EGCG) was first isol ated fro m purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v). The molecular structure of the acyl-derivative, Epigallocatechin-3-O- gall ate-4\'-O-hexadecanate, was elucidated by means of elemental analysis, I R, ¹H-NMR and MS spectra.

The optimization of cultural conditions for β-glucanase production by Bacillus subtilis ZJF-1A5 was investigated in flask trials. Temperature had great effect on β-glucanase production which maximized at optimal temperature of 37 °C and decreased significantly when temperature was over 37 °C. Charge quantity affected β-glucanase production significantly. Adding oxygen vector N-dodecane or acetic ether benefited β-glucanase production, but it depended on the concentration and charge quantity. The results of fractional factorial design showed that age and size of inoculum and shaking speed were the key factors affecting β-glucanase production and the cultivation time span to reach the highest β-glucanase activity. The optimal cultural conditions for β-glucanase production obtained with CCD were as follows: inoculum age and size (16 h, 3.82%(v/v)), shaking speed 2 10 r/min, charge quantity of 30 mL in 250 mL flask and initial pH 7.0, cultured at 37 °C for 50 h. Repeated experimental results accorded with those predicted by a second-order polynomial model. The amount of β-glucanase, α-amylase and neutral protease produced by B subtilis ZJF-1A5 was associated partially with cell growth. Those three enzymes\' activities increased following the cell growth and increased significantly when cells entered the stationary phase.

Analyses of the correlation between hyperspectral reflectance and pigment content including chlorophyll-a, chlorophyll-b and carotenoid of leaves in different sites of rice were reported in this paper. The hyperspectral reflectance of late rice during the whole growing season was measured using a Spectroradiometer with spectral range of 350-1050 nm and resolution of 3 nm. The chlorophyll-a, chlorophyll-b and carotenoid contents in rice leaves in rice fields to which different levels of nitrogen were applied were measured. The chlorophyll-a content of upper leaves was well correlated with the spectral variables. However, the correlation between both chlorophyll-b and caroteniod and the spectral variables was far from that of chlorophyll-a. The potential of hyperspectral reflectance measurement for estimating chlorophyll-a of upper leaves was evaluated using univariate correlation and multivariate regression analysis methods with different types of predictors. This study showed that the most suitable estimated model of chlorophyll-a of upper leaves was obtained by using some hyperspectral variables such as SD_r, SD_b and their integration.

Chinese Meishan and Jiangquhai pigs are two of the most prolific pigs in the world, but their growth rate is lower than that of Duroc, Landrace and Pietrain pigs. It is suggested that growth rate is regulated by growth hormone. The objective of the current study was to analyze the porcine growth hormone (pGH) gene polymorphisms based on the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP) for three western meat-type breeds (Duroc, Landrace and Pietrain) and two local Chinese pigs (Meishan and Jiangquhai). Five polymorphic restriction sites were detected with the ApaI, MspI, BspI and HhaI restriction enzymes in two amplified fragments (605 bp, -119 to +486; 506 bp, +206 to +711). Breed difference was found only in the 506 bp fragment. There was no difference in allelic frequencies of BspI and HhaI restriction sites among the five breeds (P>0.05). Landrace and Meishan pigs lacked allele G3 of MspI site. The allele G3 frequency of restriction MspI site of the 506 bp fragment in Pietrain pigs was higher than that in Duroc and Jianquhai pigs (P<0.001). For ApaI site, the Meishan pigs lacked allele G1; no difference was found in allelic frequencies among Pietrain, Duroc, Landrace and Jiangquhai pigs (P>0.05). This new and rapid PCR-RFLP typing method is an attractive tool for analysis of porcine growth hormone gene restriction sites. The differences in MspI and ApaI restriction sites may explain the growth difference between the foreign meat-type breeds above mentioned and local Chinese pigs.

The p-norm joint spectral radius is defined by a bounded collection of square matrices with complex entries and of the same size. In the present paper the author investigates the p-norm joint spectral radius for integers. The method introduced in this paper yields some basic formulas for these spectral radii. The approach used in this paper provides a simple proof of Berger-Wang\'s relation concerning the ∞-norm joint spectral radius.

Objective: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation (AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60°C. The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132±68 min for our patients. The average fluoroscopy time was 33±17 min. With a mean follow-up of 16±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

Objective: To explore the frequency and significance of ApoE gene polymorphisms in Chinese patients with atherosclerotic cerebral infarction (ACI). Methods: Polymerase chain reaction and gene sequencing, single nucleotide polymorphisms of ApoE gene were used to analyze 33 cases of patients with ACI and 35 controls. Results: The frequencies of ApoE gene single nucleotide polymorphisms 465C/G, 462C/G and 451delC in the ACI group were significantly higher than those in the control group (P<0.05). The prevalence of polymorphism 486G/T in the control group was significantly higher than that in the ACI group (P=0.011). Conclusions: 465C/G,462C/G and 451delC polymorphisms might be associated with ACI.486GT allele might have protective effect on the pathogenesis of ACI.

This study was aimed to investigate the relationship between breakfast and serum glucose, insulin and glucagon concentrations in order to establish a model breakfast appropriate for Chinese. Twenty-four volunteers were randomly assigned to four study groups: high carbohydrate breakfast, high fat and protein breakfast, the typical breakfast and fasting. Each subject had serum and urine samples collected while fasting and at 1,2 and 3.5 hours following the meal. The concentration of serum glucose, insulin and glucagon was measured. The levels of serum glucose in group A,B and C differed significantly at 1 and 2 hour after meal compared to those at fasting (P<0.05). The serum glucose in group A increased insignificantly after meal. The serum insulin levels were in group A,B and C significant different compared with control group(P<0.05).Those peaked at 1 hour after meal,with group C rising the furthest. Compared with the fasting group, the serum glucagons rose and maintained the increase after breakfast in group A,B and C (P<0.05).The data suggested that various diets with different calorigenic amounts increased hormone concentration to various extents. We found that a breakfast rich in carbohydrates could maintain proper blood glucose level.