南京东路消费者的回游消费行为研究

延续对上海南京东路商业街消费者的“入口消费行为”研究,研究消费者的“回游消费行为”。引入马尔可夫链(MarkovChain)模型,并证明该方法可以准确地测算商业空间的消费者活动人次。用嵌套分对数模型(nestedlogitmodel)解释消费者的空间选择行为。发现模型对南京东路消费者样本的拟合取得了良好的拟合优度,模型参数的行为意义与入口模型基本取得一致。整合入口模型、回游模型和马尔可夫模型后实施现实模拟,发现商业立地在吸引消费者过程中的重要性以及模型方法在多目的规划中应用的潜力。     

An evaluation of a modulated laser encoder

This paper introduces a new method of interpolation for sub-nanometer-resolution linear encoders. This method, called SPPE (scanning position probe encoder), uses high-order harmonics information obtained by a sinusoidal scanning pickup located on a periodic grating surface. The proposed encoder uses a current-modulated laser diode with diffractive grating optics. Since the electrical current changes the laser-diode wavelength, the interference light intensity is modulated as a sinusoidal scanning pickup on the scale grating. Phase-detection circuits can decode the position information in the pickup signal by using phase-locked loop techniques. The decoder achieves an interpolation rate of over 1/40,000 with interpolation errors of less than ±1 nm. A new interpolation-error measuring system was developed for the encoder. Finally, the evaluation results reveal that the presented encoder shows both high resolution and strong robustness.     

Multistage catalytic combustion systems and high temperature combustion systems using SiC

Multistage catalytic combustion systems for commercial applications using noble metal catalyst were investigated at conditions under 1000°C. Also, the high temperature combustion systems using SiC material were investigated at conditions up to 1400°C.     

Genotoxicity of colloidal fullerene C₆₀

Previous genotoxicity tests of aqueous fullerene C??) suspension (aqu-C??) yielded both positive and negative results. In the present study, aqu-C?? elicited positive responses in two bacterial genotoxicity tests, the Bacillus subtilis Rec-assay and the umu test at concentrations as low as 0.048 mg/L and 0.43 mg/L, respectively. In mammalian cell experiments, aqu-C?? showed a significant growth inhibitory effect on human hepatocarcinoma HepG2 cells at 0.46 mg/L. The level of the oxidative DNA lesion 8-oxo-7,8-dihydro-2'-deoxyguanosine, measured by liquid chromatography tandem mass spectrometry, was slightly but not significantly increased in HepG2 cells treated with 0.46 mg/L for 24 h, whereas the level of the lipid peroxidation-related DNA lesion α-methyl-γ-hydroxy-1,N2)-propano-2'-deoxyguanosine was not changed. Under the same conditions, we did not detect any bulky DNA adducts, as measured by 32P-postlabeling/polyacrylamide gel electrophoresis analysis. Our data suggest that aqu-C?? has DNA-damaging potential and that the DNA damage is not due to covalent DNA adduct formation by C?? itself.     

Flame stability and emission characteristics of propane-fueled flat-flame miniature combustor for ultra-micro gas turbines

An engineering model of a propane-fueled miniature combustor was developed for ultra-micro gas turbines. The combustion chamber had a diameter of 20 mm, height of 4 mm, and volume of 1.26 cm³. The flat-flame burning method was applied for lean-premixed propane–air combustion. To create the stagnation flow field for a specific flat-flame formation, a flat plate was set over the porous plate in the combustion chamber. A burning experiment was performed to evaluate the combustion characteristics. The flame stability limit was sufficiently wide to include the design operation conditions of an equivalence ratio of 0.55 and air mass flow rate of 0.15 g/s, and the dominant factors affecting the limit were clarified as the heat loss and velocity balance between the burning velocity and the premixture flow velocity at the porous plate. CO, total hydrocarbons (THC), and NO_x emission characteristics were established based on the burned gas temperatures in the combustion chamber and the temperature distribution in the combustor. At an air mass flow rate of less than 0.10 g/s, CO and THC emissions were more than 1000 ppm due to large heat loss. As the air mass flow rate increased, the heat loss decreased, but CO emissions remained large due to the short residence time in the combustion chamber. NO_x emission depended mainly on the burned gas temperature in the combustion chamber as well as on the residence time. To reduce emissions despite the short residence time, a platinum mesh was placed after the combustion chamber, which drastically decreased the CO emissions. The combustor performance was compared with that of other miniature combustors, and the results verified that the present combustor has suitable combustion characteristics for a UMGT, although the overall combustor size and heat loss need to be reduced.     

Electric Dipole Tracing in the Brain by Means of the Boundary Element Method and Its Accuracy

A method of localizing an electrical dipole in the brain from the scalp potential distribution has been developed with the aid of the boundary element method, in which a real geometry of the head is exactly taken into account and homogeneous electrical conductivity is assumed. Accuracy of the method was evaluated through animal experiments with a cat in which a current dipole was artificially generated in the brain. Deviation of the estimated dipole location from the true one was not random, but rather systematic (probably due to in-homogeneous conductivity distribution). It is numerically found that cavities in the skull disturb the inverse solution especially when the dipole is oriented toward the cavities. In vivo tests of the method were also done for primary somatosensory evoked potentials as a response to median nerve stimulation of a cat and myoclonic EEG. Although the homogeneous approximation was made, it does not change the significance of the results obtained by the present method.     

A non-blocking locking method and performance evaluation on network of workstations

A network of workstation(NOW) can act as a single and scalable powerful computer by building a paralle and distributed computing platform on top of it.WAKASHI is such a platform system that supports persitent object management and makes full use of resources of NOW for high perforance transaction processing,One of the main difficulties to overcome is the bottleneck caused by concurrency control mechanism.Therefore,a non-bloking locking method is designed,by adopting several novel techniques to make it outperform the other typical locking methods such as 2PL:1) an SDG (Semantic Dependency Graph)based non-blocking locking protocol for fast transaction scheduling;2) a nmassively virtual memory based backup-page undo algorithm for fast restart;and 3) a multi-processor and multi-thread based transaction manager for fast execution.The new mechanisms have been implemented in WAKASHI and the performance comparison experiments have been implemented in WAKASHI and the performance comparison experiments with 2PL and DWDL have been done.The results show that the new method can outperform 2PL and DWDL under certain conditons.This is meaningful for choosing effective concurrency control mechanisms for improving transaction-rpocessing performance in NOW environments.     

Studies on the biaxial stretching of polypropylene film. VII. Refractive index of film measured with abbé refractometer

The refractive index of a film measured with an Abbé refractometer differs often depending on which surface of the film faces the refracting prism of the refractometer. This phenomenon was elucidated by using well-characterized films especially prepared for the purpose. The experimental results led to the conclusion that the measurement with an Abbé refractometer gives the refractive index of the film surface facing the refracting prism independently of the refractive index distribution within the film. The importance of this conclusion is stressed in relation to the structural studies of polymer films, especially of biaxially stretched films.