A speaker-independent connected digit recognition systemconcatenating statistically discriminated words

A recognition system for connected digits, which uses a statistical classifier to identify words in speaker-independent continuous speech, is described. The system uses the multiple similarity method, a statistical pattern recognition technique. For evaluating word strings, the system uses a scoring method that is independent of the number of words in the strings. It is derived from the a posteriori probability that a subinterval corresponds to a correct word position, giving a word similarity value. The system evaluates a word string using dynamic programming and a parallel search procedure. Experiments for the contextual effect of the training data set, for validation of the search algorithm, and for a large quantity of unspecified speakers including 40 males and 40 females were performed. For connected digits (unknown word lengths test), the string recognition rates were 90.1%-95.1% for two, three, or four connected digits, where the equivalent word (digit) rates were 97.4%-98.4%     

A 21-mW 4-Mb CMOS SRAM for battery operation

The authors describe a 21-mW 4-mB CMOS SRAM for the application of memory systems which operate on 3-V batteries. A low active power is achieved by novel circuit technologies. A thin-film transistor (TFT) load memory cell effectively reduces standby current to 0.4 μA. A new multibit test circuit, which permits measurement of access time, is also introduced for a reduction of the test time. The authors describe the characteristics of the TFT memory cell and the improved memory cell design for stable cell operation. The 0.6-μm process technology used to fabricate the 4-Mb SRAM and the chip performance are outlined     

Study on the potential of farmland soils as non-point sources of nitrogen and phosphorus in Japan.

The amounts of N and P accumulated in farmland soils of 50 cm depth were equivalent to the amount of chemical fertilizer supplied for 50-70 years. The values of N/P of surface soils in farmlands were 1.0-4.3, lower than expected. The median diameter of soil particles in run-off waters was generally less than 10 microm. The mean values of particulate fractions over 1 microm and over 0.22 microm were 19% for N, 27% for P, and 39% for N, 64% for P respectively. Fine particles of soil containing concentrated phosphorus should be carefully monitored as potential sources related to eutrophication.     

Optical tweezers and fluid characteristics of an optical rotator with slopes on the surface upon which light is incident and a cylindrical body

The characteristics of the optical trapping force, optical torque, and viscous drag force for a newly proposed cylindrical optical rotator are analyzed. The optical trapping force and torque are evaluated by use of a ray optics model for both parallel and focused laser beam illumination. The drag force is calculated from computational fluid dynamics to be the sum of the components of both the pressure and the shearing stress on all the surfaces of the rotator. We analyze the rotation rate by balancing the optical torque with the drag force. A cylindrical optical rotator is expected to rotate at a high speed because of its highly efficient generation of optical torque and its small viscous drag force.     

Fluid filter fabricated by deep X-ray lithography for micro fluidics

A new method and fluid filter with micro through capillary array for high-throughput micro fluidics were proposed and fabricated. The method, utilizing liquid surface tension and directing fluid flow in vertical direction, was achieved by using the fluid filter we originally proposed. The computational fluid dynamics analysis was conducted to examine the feasibility of vertical fluid flow operation using the fluid filter. And the results indicated that the vertical fluid flow operation is useful and the good properties of the fluid filter. Fabrication of fluid filter was successfully conducted by using deep X-ray lithography. And vertical fluid flow operation and its high throughput properties were successfully demonstrated.     

Probabilistic-topological calibration of widely distributed camera networks

We propose a method for estimating the topology of distributed cameras, which can provide useful information for multi-target tracking in a wide area, without object identification among the fields of view (FOVs) of the cameras. In our method, each camera first detects objects in its observed images independently in order to obtain the positions/times where/when the objects enter/exit its FOV. Each obtained data is tentatively paired with all other data detected before the data is observed. A transit time between each paired data and their x–y coordinates are then computed. Based on classifying the distribution of the transit times and the x–y coordinates, object routes between FOVs can be detected. The classification is achieved by simple and robust vector quantization. The detected routes are then categorized to acquire the probabilistic-topological information of distributed cameras. In addition, offline tracking of observed objects can be realized by means of the calibration process. Experiments demonstrated that our method could automatically estimate the topological relationships of the distributed cameras and the object transits among them.     

Planar microreactor for biochemical application made from silicon and polymer films

Recently the progress of life science has been increasing rapidly, and the importance of the microfluidics for DNA analysis systems has been widely recognized, especially in medical fields. The polymerase chain reaction (PCR) is an essential technique for DNA assay of various diseases and it has been a strong requirement to shorten the total of PCR cycles more and more. We developed the microreactor with a single cell for PCR using fabrication technologies of MEMS. The reactor body and cover were sealed using high thickness PDMS prototyping film without using adhesive in order to achieve repeat grabbing motion for direct sample injection, resumption and cleansing the reaction cell. Good reproducibility of the heat cycling was obtained. The heating rate and cooling rate during PCR was 6.8 and 2.7°C, respectively, which well corresponds to the design parameters. The homogenous temperature distribution of variance less than 2.0°C was obtained. It is demonstrated that amplification of the DNA was successfully achieved by using the microreactor.     

Enzyme-linked immunosorbent assay for nonylphenol using antibody-bound microfluid filters in vertical fluidic operation

We developed an enzyme-linked immunosorbent assay for an endocrine disrupter, nonylphenol, using a microreactor composed of two reaction vessels stacked vertically through a microfluid filter. The filters constructed by deep X-ray lithography possessed 2100 through-bores (phi40 x 200 microm) in polymethylmethacrylate sheets (phi3 mm), which are appropriate for biochemical reactions. Through the optimization of the immunoassay, nonylphenol was quantitatively detected at the range of 0.1-10 ng/ml.     

Fabrication of a micro reactor for vertical unit operation using multifunctional fluid filter and its application to biochemical reaction

We proposed and fabricated a vertical micro reactor stack with vertical fluid flow operation for environment analysis, post-genome analysis, gene diagnosis, and screenings of useful materials for pharmaceutical. This reactor is characterized as the simple structure and new aspects of the vertical fluid transportation evoked by the use of the fluid filter with micro through-bores. The lithographite, galvanoformung and abformung (LIGA) process using synchrotron radiation was applied for the fabrication of the fluid filters. The computational fluid dynamics (CFD) simulation results suggested that the fluid can be held by the fluid filter and easily transported by the pneumatic operation. It was also confirmed that the fluid flow velocity through the filter was controlled by varying the loaded pressure around several kPa. Furthermore, it was expected that the fluid was stirred and mixed when passing through the fluid filter. It was demonstrated that the proposed chemical reactor result in a good performance of the vertical fluid flow operation and biochemical reaction.