Toward a compression-based self-organizing recognizer: Preliminary implementation of PRDC-CSOR

The present paper introduces a new data analyzer, a compression-based self-organizing recognizer, the PRDC-CSOR (Pattern Representation scheme using Data Compression – Compression based Self ORganizing Recognizer), with a preliminary application to image data. The PRDC-CSOR is an extension of the authors’ previously proposed pattern representation scheme using data compression (PRDC). Contrary to the traditional statistical-model-based recognition system methods, the PRDC-CSOR constructs itself using incoming data only. The basic tool, compressibility, is an approximation of the Kolmogorov complexity K(x)$K(x)$ defined in an individual text x   as a countermeasure against the Shannon entropy H(X)$H(X)$ defined on an ensemble X. Due to this feature, a highly automatic self-organizing recognition system becomes possible as demonstrated in this paper.     

A control strategy for leveling load power fluctuations with a successive learning fuzzy-neural network based on prediction of average load power

The effective usage of power facilities can be realized by leveling the fluctuating active power and compensating the reactive power. A fuzzy control strategy of superconducting magnetic energy storage (SMES) has been proposed for this purpose. The control results depend on the values of the scaling factors in fuzzy reasoning. Therefore, to obtain better control results, the scaling factor should be successively adjusted according to the load power fluctuations. In this paper, a control strategy based on autotuning of scaling factors and a fuzzy singleton reasoning method using backpropagation in a neural network is proposed for leveling load fluctuations. The prediction and revision of the teaching signal in terms of the energy of the SMES is proposed. The learning rate and the revision of the teaching signal are discussed. Better leveling of load power fluctuation is shown to be achievable by using fuzzy logic and neural networks. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(2): 72–81, 1997     

Individual differences on diurnal variations of the task performance

In order to understand psychophysiological background of the individual differences on the diurnal variation of task performance, the task performance (i.e. the number of a simple adding calculation performed in one minute) was measured from 09:30 in the morning to 21:30 in the late evening for 9 healthy university male students. Heart rate (HR) and body temperature were also continuously recorded for 35 hours. There were two different types in the diurnal variation of the task performance; the morning type who shows the best performance in the morning, and the evening type who shows it in the evening. The body temperature curve during daytime in the evening type goes gradually up to the evening, on the contrary, that in the morning type rapidly rises to the maximum point in the morning or the afternoon. HR during daytime were higher in the morning type than the evening type. These results indicate that the morning type has a tendency of the higher mental tension compared with the evening type. And they also suggest that the individual differences on the task performance with a large mental concentration are caused by some kinds of subject's psychosomatic state.     

An evaluation of metal and semiconductor films formed by ionized-cluster beam deposition

The mechanism of film formation and the properties of films deposited by the ionized-cluster beam technique were investigated. In this technique, strong adhesion of the film to the substrate and good crystalline deposition are expected.A high adhesive strength of over 100 kg cm^-2 for Cu films on glass substrates was obtained in the experiments. The migration of adatoms consisting of ionized and neutral clusters was observed on the substrte surface. This effect, called the migration effect, can be considered to characterize film formation by cluster beam deposition and to produce good crystalline films. Si single crystals were obtained on Si substrates. A p-n junction photodiode was fabricated by the deposition of n-type Si on a p-type substrate. The diode shows improved spectral sensitivity in the UV region compared with that of commercially available solar cells.     

Consolidation of Eutectic Powder of Al2O3–GdAlO3

A eutectic solid of Al₂O₃–GdAlO₃ was prepared by arc discharge and crushed to a eutectic powder of 3–125 μm. The powder was consolidated by the spark plasma system (SPS). The consolidated powder duplicated the eutectic structure: Al₂O₃ and GdAlO₃ were joined to each crystal. There were no flaws such as cracks or pores in the eutectic composite. The bending strength was half that of the eutectic composite prepared by unidirectional solidification.     

Copper-mediated growth of amyloid β fibrils in the presence of oxidized and negatively charged liposomes

Amyloid β protein (Aβ) from Alzheimer's disease formed fibrillar aggregates and their morphology depended on oxidized and negatively charged liposomes. The morphology of fibrillar aggregates was affected by Cu²⁺, together with their growth kinetics. This is because Cu²⁺ inhibited the nucleation step in the formation of amyloid Aβ fibrillar aggregates by forming Aβ/Cu complex inactive to the growth of fibrillar aggregates. In addition, this is probably because Cu²⁺ affected the fibrillar aggregate formed on the surface of liposomes. These findings would give a better understanding of the formation mechanism of amyloid fibrils on biomembranes.     

Flame structures and combustion efficiency computed for a Mach 6 scramjet engine

Our hydrogen-fueled scramjet engines with a length of 2.1 m delivered net thrusts exceeding the engine drags and exhibited fuel specific impulses of about 10 km/s under Mach 4 to 8 flight conditions. A three-dimensional, reactive CFD code using unstructured hybrid grids was developed to accelerate the engine studies. Combustion in the scramjet engine under the Mach 6 condition was simulated by using this code. In this paper, the engine testing and the CFD code were outlined first. Timewise progress of hydroxyl radicals was investigated to understand autoignition and upstream-wise developments of combustion in the engine. Autoignition occurred from the cowl section at 0.1 ms after fuel mixing was completed. The reaction zones propagated upstream at speeds of about 500 m/s and reached the backward-facing steps in the combustor at 1 ms after the autoignition. Steady-state solutions showed small flames around individual fuel jets in the combustor and a large-scale diffusion flame downstream in the engine. Sonic combustion was autonomously realized in the combustor, resulting in delivery of a maximum thrust of 2250 N in the stoichiometric condition. Variations of combustion efficiency indicated that combustion performance was determined in a narrow region with a length of 0.15 m in the combustor and that the combustion downstream of the engine was rate-controlled by a large diffusion flame. The results found by the CFD computations enable us to not only improve engine performances but also to optimize computations for scramjet engines.     

Adhesive,Flexible, and Robust Polysaccharide Nanosheets Integrated for Tissue‐Defect Repair

Recent developments in nanotechnology have led to a method for producing free‐standing polymer nanosheets as a macromolecular organization. Compared with bulk films, the large aspect ratio of such nanosheets leads to unique physical properties, such as transparency, noncovalent adhesion, and high flexibility. Here, a biomedical application of polymer nanosheets consisting of biocompatible and biodegradable polysaccharides is reported. Micro‐scratch and bulge tests indicate that the nanosheets with a thickness of tens of nanometers have sufficient physical adhesiveness and mechanical strength for clinical use. A nanosheet of 75 nm thickness, a critical load of 9.1 × 10⁴ N m^?1, and an elastic modulus of 9.6 GPa is used for the minimally invasive repair of a visceral pleural defect in beagle dogs without any pleural adhesion caused by wound repair. For the first time, clinical benefits of sheet‐type nano‐biomaterials based on molecular organization are demonstrated, suggesting that novel therapeutic tools for overlapping tissue wounds will be possible without the need for conventional surgical interventions.     

Effects of Bi and Pb on oxidation in humidity for low-temperature lead-free solder systems

The oxidation behavior of various Sn-Zn(-Bi) alloys during 60°C/90% and 85°C/85% relative humidity (RH) exposure were investigated by microstructure observation and x-ray diffraction analysis. The mechanical property of the joints of resistor chips (1608R) with two kinds of terminations, Sn and Sn-10Pb, soldered on a printed circuit board with Sn-Zn(-Bi) were evaluated by a shear test. The heat/humidity exposure of Sn-Zn alloys promotes segregation into the grain boundary accompanying oxidation of Zn resulting in the ZnO formation. This segregation induces serious degradation of alloys and Sn whisker growth. Heat/humidity exposure of 85°C/85%RH seriously decreases the shear strength of the surface mounted chip joints, especially Sn-Zn-Bi solder, due to the formation of ZnO at the interface between the solder and the reaction layer. The presence of Bi or Pb in Sn-Zn alloys enhances the diffusion, resulting in severe degradation at 85°C/85%RH exposure. In contrast, the exposure at 60°C/90%RH does not influence the joint strength for up to 1000 h. Under this condition, the oxidation of Zn only reaches a few microns in depth from the free surface.