The research of organic devices aiming at the large-area and low-cost products by printing technologies attracts attention in addition to the light weight, flexibility. In other words, the printing methods are more useful from the viewpoint of low temperature, energy saving, low environmental load than a conventional inorganic semiconductor device manufacturing such as vacuum, high temperature, photolithography processes in clean room. This paper describes the basic concept of molecular technology aimed at the liberty control of molecules and the new application fields of the organic electronic devices including our recent researches based on printing technology which is expected for low-cost process.
A new micro-electrode structure for Hall-effect measurements of organic semiconductor layers was proposed. The equations for the Hall-effect measurements based on the van der Pauw method indicate that narrower electrode gaps can decrease the resistance between contact points and enable Hall-effect measurement even for higher resistance materials such as organic semiconductors. According to this “scaling rule”, we fabricated a new electrode chip which consists of four small finger electrodes with a gap of micrometer-scale between diagonally opposite electrodes. In order to demonstrate the validity of this concept, Hall-effect measurements for FeCl3-doped poly(3,4-ethylenedioxythiophene) (PEDOT) was performed using this new electrode structure, revealing that a 10-μm-gap electrode chip is effective for evaluating carrier concentration of down to around 1019cm-3. These Hall electrode chips are quite useful for quantitative analysis of carrier concentration and carrier mobility in organic semiconductor materials.
Polymer thin films having oxiadiazole unit were prepared by the electron-assisted vapor deposition polymerization of its vinyl derivative (vPBD). Chemical analyses showed that the deposited film contained 60% of polymer component having molecular weight of several thousands. The result was applied for constructing an emissive layer (EML) of an organic light emitting diode (OLED). The EML was prepared by coevaporating vPBD with a vinyl derivative of an iridium complex (vIr(ppy)3). The emission spectra suggested that the dopant units are copolymerized into the main chain of vPBD host polymer. Comparison was made with an EML that consisted of the standard oxadiazole host material (tBu-PBD) having no polymerizable functional group. The OLED having deposition-polymerized EML gave higher luminance compared to the device prepared without polymerization. Moreover, the device lifetime was improved as a consequence of deposition polymerization. The electron-assisted deposition of vinyl compounds can be an effective method to improve the device performance of OLEDs through the formation of stable polymer thin films, in which the dopant molecules are copolymerized uniformly.
By applying large A.C. square voltages to double-layer ITO/α-NPD/Alq3/Al devices, we studied the generation of electroluminescence (EL) in terms of the carrier injection and transport. The EL intensity gradually decayed with the increase of the frequency of the applied A.C. square voltage, and reached a minimum at the frequency corresponding to the carrier transit time. Interestingly, the EL intensity was again increased by the application of further higher frequency A.C. square voltages, relying on the D.C. component of the A.C. square voltages. The results suggested the presence of two EL modes. Using the Maxwell-Wagner effect model analysis, we proposed a model that accounts for the presence of two EL modes.
Fluoropolymer thin films were deposited by vapor deposition polymerization of 2-(perfluorohexyl) ethylacrylate (Rf-6) under irradiation by low energy Ar ions. Polymerization of Rf-6 was enhanced by increasing the ion energy, while no films were obtained without the ion irradiation. However, the surface energy also increased with increasing ion energy. At the optimum energy of 100 eV, uniform fluoropolymer thin films having surface energy of 10mJ/m2 were obtained. The films were insoluble to organic solvents. The film had low refractive index of 1.371, which makes it attractive as an antireflective coating. By depositing a 100-nm thick polymerized film of Rf-6, the reflectivity of a glass substrate was reduced by 3.37% at a wavelength of 590nm. It is expected that the deposition-polymerized films of Rf-6 is attractive as antireflective and antipollution coatings on flexible devices.
By combining the two concepts of superlattice and organic amorphous materials, we attempted to fabricate a new material that shows photo-switching piezoelectric properties. In order to utilize the merit of amorphous materials that can be deposited quickly, we started from building an equipment specialized to fabricate organic amorphous superlattices. By using this equipment, we fabricated p-type semiconductor / piezoelectric polymer / n-type semiconductor superlattice that responded to photo-irradiation both electrically and mechanically.
Fibroblast L929 and myoblast C2C12 cells of the mouse connective tissue origin were sown on the surface of conductive polymer films (polypyrrole, PPy and poly(3,4-ethylenedioxythiophene), PEDOT) in the cell culture medium, and the proliferative process of these cells was observed. Without changing the form, fibroblast L929 and myoblast C2C12 cells were observed to proliferate almost similarly to the cell which cultured on a dish on the market and to maintain compatibility. In other word, it has been understood that these two kinds of conductive polymers used in this study, the PPy and PEDOT films maintain the secretion function of the cell cultured on the surface of these polymers. Therefore, the PPy- and the PEDOT-coated electrode suggested the possibility usable as a nerve stimulation electrode with biocompatibility, because these polymers were effective to culture the cell.
A self-biased channel diode (SBCD) that self-biases a channel diode using a DMOSFET structure has recently been proposed. In the present paper, an analytical simulation method, based on a drift-diffusion model that takes into account the physics of the SBCD, is described and the simulation results are presented. The simulation results are seen to be in good agreement with the experimental results. An increase ratio of a reverse leakage current of the SBCD for temperature is significantly less than that of the Schottky barrier diode (SBD). This relative insensitivity of the SBCD reverse current to rising temperature can be explained in terms of the temperature dependence of the parameters composed of the reverse leakage current by the analytical simulation. Furthermore, the power loss is simulated for a SBCD with a thin gate oxide layer, integrated into a high-density DMOSFET cell. The SBCD impurity profile is chosen to correspond to an approximate minimum power loss at 75°C for a gate oxide thickness of 3nm. Under these conditions, the SBCD exhibits a power loss intermediate between that of the Ti-SBD and Cr-SBD in the temperature range 25-75°C. However, at high temperatures, the power loss in the SBCD is lower than that for the Ti-SBD or Cr-SBD, which easily undergo thermal runaway.
We have proposed a new eye blink detection method that uses a home video camera. This method utilizes split interlace images of the eye. These split images are odd- and even- field images in the NTSC format and are generated from NTSC frames (interlaced images). This proposed method yields a time resolution that is double that in the NTSC format. That is, the detailed temporal change occurring during the process of eye blinking can be detected. However, this method yields vertical space information that is half that in full sized NTSC images. To improve this point, we apply a hi-vision camera to measure eye blink by our proposed method. In the result, the dynamic range of eye blink detection increases. Further, we propose a new method to extract the wave pattern at eye blinking. By using this method, the eye blink can be extracted from the detection result automatically. The extraction method classifies the wave pattern at eye blinking by using the statistical information of eye blinking wave pattern.
This paper deals with H∞ filter-based short-term electric load prediction considering characteristics of load curve. We propose a predictive method to forecast a future electric load demand for 36 hours from 0 PM, and then evaluate the peak and bottom of load curves in the next day. We propose a load model, estimates unknown parameters of model via H∞ filter using the separated data from holiday and weekday, a same pattern of the previous data have been chosen and assigned to parameters for the model. The simulation results show the effectiveness of the proposed prediction methodology.
It is important for maintenance to detect the rubbing phenomenon of the sliding bearing in the early stage. The experiment of a slight rubbing condition conducted and the change of vibration was examined. Importantly, the fact newly found is that peaks in spectrum domain with rotational frequency period take place due to rubbing. As a result, the Cepstrum analysis was proved to be effective for the detection of rubbing in its early stage. A device, which can follow the level of quefrency, was developed based upon this idea, so that utilizing the device is highly efficient to monitor the sliding bearing condition.
In multivariable systems, controlled variables interact each other in general. Therefore it is difficult for the classical control theory such as PID control to control multivariable systems. The Nyquist Array method as the practical design technique has been used for the long time. However the method becomes fairly complicated when we design a precompensator and PID controller. Therefore we propose the PID controller design method for multivariable systems which can realize PID control relatively easily in view of utility. We design a compensator which meets the diagonal dominance using Real Code Genetic Algorithms. Next, we design the PID controller using Coefficient Diagram Method which takes simultaneously good balance of stability, response, and robustness by using coefficient diagram. Finally, the effectiveness of the proposed method is confirmed with the simulation results.
In this paper, we propose a task estimation method based on multiple subspaces extracted from multi-modal information of image objects in visual scenes and spoken words in dialog appeared in the same task. The multiple subspaces are obtained by using latent semantic analysis (LSA). In the proposed method, a task vector composed of spoken words and the frequencies of image-object appearances are extracted first, and then similarities among the input task vector and reference sub-spaces of different tasks are compared. Experiments are conducted on the identification of game tasks. Experimental results show that the proposed method with multi-modal information outperforms the method in which only single modality of image or spoken dialog is applied. Moreover, the proposed method achieved accurate performance even if less spoken dialog is applied.
In music information retrieval, a huge search space has to be explored because a query audio clip can start at any position of any music in the database, and also a query is often corrupted by highly significant noise and distortion. Audio fingerprints have attracted much attention recently for providing compact representation of the perceptually relevant parts of audio signals. In this paper, we propose an extremely fast method of exploring a huge hamming space for audio fingerprinting systems. The effectiveness of our method has been evaluated by experiments using databases of 8,740 real songs and 800 artificially corrupted and 268 real queries.
The necessity of distinguishing of the road surface condition at night-time is increasing because most of the previously proposed method corresponds only to daytime. In this paper, we propose a distinction method of road surface condition by using only video information acquired from visible surveillance video camera. The feature of this method is simply to use the cars' headlights as the light source. As the result, it became possible to distinguish the road surface conditions such as dry and wet with high accuracy by using this method.
Video surveillance using intelligent camera system is widely used in many areas such as traffic control, driving assistance and surgery. But, image acquisition of large viewing field for video surveillance make unfeasible use of multiple camera system or mechanically controlled cameras. To solve this problem, omnidirectional camera system using panoramic annular lens may be used with many advantages such as compactness and unnecessary calibration. Nevertheless, low spatial resolution of angle of elevation for vertical direction of captured image using PAL may incur drawbacks such as quality degradation for image after panoramic expansion. To overcome these disadvantages, the high quality panoramic image generation method is required. Therefore, we propose the high quality panoramic image generation method using multiple panoramic annular lens images. By synthesizing multiple PAL images at different zoom rates, we can obtain fine quality panoramic image.
We propose a robust face detection algorithm using one-class estimation and Real AdaBoost. Inspired by the first practical face detection algorithm by Viola and Jones, many varieties of face detection algorithms have been proposed. The common feature of their algorithm is a cascaded structure of combined Haar-like features trained by a boosting algorithm. Of course this framework has achieved a successful result of high detection rate and low false positive rate in a short time and has been applied to many imaging products. But because the non-face class includes multiple sub-classes and their variations are too many to be collected and covered in training data, unexpected false positives inevitably happen in the real world data. That is a problem of self-printing systems for digital cameras because they need to handle all kinds of pictures in the real world. Furthermore because they use detected face regions for image enhancement before printing, to suppress false positives is a big issue of self-printing systems. To solve the problem of false positives in the real world, we model a non-face class using one-class estimation of faces, and developed a new face detection algorithm combining one-class estimation and a cascaded face detection by Real AdaBoost. As a result of the experiment using pictures of digital cameras, we achieved about twice faster face detection with eight times lower false positives than a conventional cascaded face detector, and also more precise face size detection.
In this paper, a musical instrument and pitch estimation method of polyphonic music signals for automatic transcription is proposed. The method consists of three main stages. First, spectrum of polyphonic musical signal is calculated to extract audio features using short-time FFT (Fast Fourier Transform). Next, the polyphonic music signal is decomposed to monophonic music signals based on HC (Harmonic Clustering) in log scale frequency domain. Finally, musical instrument of the signals is identified with tone database using GMM (Gaussian Mixture Model) or SVM (Support Vector Machine) applied to MFCC (Mel-Frequency Cepstrum Coefficient). Pitch is sequentially estimated using the extracted power spectrum peaks information with pitch database. Simulation results are given to demonstrate the effectiveness of tone and pitch estimation of polyphonic music signal with various combinations of musical instruments using RWC (Real World Computing) music database system.
This paper proposes a method of fast tracking of feature points in the fisheye full-view image captured from a fisheye full-view image sensor. The fisheye full-view image consists of a pair of fisheye sub-images. Each fisheye sub-image of the full-view image sensor has wider field of view than a hemisphere. The local region of feature points of scenes changes abruptly when the feature points move from one of the pair of fisheye sub-images to the other due to the heavy distortion of fisheye images. In this paper, the tracking of feature points is performed via a spherical model. The similarity of local regions of feature points is measured by the normalized image patch of the local region based on the spherical model. In the tracking process, the Kalman Filter is used to predict the location of feature points based on the spherical model. In the experiment, the processing speed with 14 full-view frames per second is achieved on a PC.
This paper describes a method of readability assessment for web documents. Readability is the ease in which text can be read and understood. We hypothesize that the readability is determined whether a reader can easily grasp text structures. The impression and the complexity of text are significant factors. We extract the features about impression and complexity from a plain text and additional data such as HTML tags. In order to compare effect of extracting features, we are assessing readability rank by machine learning. We conduct 5-fold cross validation for each domain, and calculate the root mean squared error between the actual rank and the estimated rank. The cross validation experiments confirm that the performance of our method is high measured. It shows effectiveness of extracting features about the impression and the complexity for readability assessment.