Avoiding Routing Loops on the Internet

Suppose that some particular link in the Internet is currently congested. A natural solution is to try to make packets bypass that link. This can be done by increasing the cost of that link intentionally, say from a ₁ to a ₂, since the Internet uses shortest-path routing. Unfortunately, however, this often causes temporary loops for packet traveling, called routing loops. In this paper we show that routing loops can be avoided by increasing the cost of the link not directly from a ₁ to a ₂ but through an intermediate value, a ₃, i.e., from a ₁ to a ₃ and then to a ₂. We may need several intermediate values. We show that in this case the greedy strategy, namely, raising the cost as much as possible in each step, is optimal.     

Parallel processing circuit of line image using neuristor

A simultaneous detecting circuit system of centers and lengths of some lines in one dimension is presented applying an electronic circuit model of the nervous axon with respect to signal transmission. This model consists of series of one basic section, and has functions of Neuristor. The circuit system has a paralell processing function. It is constructed by three layers. In the first layer each visual signal of lines is changed to electric pulse signal. In the second layer edges of each line are detected, and in the third layer these detected signals are converted into voltages which correspond to lengths of the lines. These functions were confirmed experimentally using its hardware.     

Improving the Performance of Feedforward Neural Networks by Noise Injection into Hidden Neurons

The generalization ability of feedforward neural networks (NNs) depends on the size of training set and the feature of the training patterns. Theoretically the best classification property is obtained if all possible patterns are used to train the network, which is practically impossible. In this paper a new noise injection technique is proposed, that is noise injection into the hidden neurons at the summation level. Assuming that the test patterns are drawn from the same population used to generate the training set, we show that noise injection into hidden neurons is equivalent to training with noisy input patterns (i.e., larger training set). The simulation results indicate that the networks trained with the proposed technique and the networks trained with noisy input patterns have almost the same generalization and fault tolerance abilities. The learning time required by the proposed method is considerably less than that required by the training with noisy input patterns, and it is almost the same as that required by the standard backpropagation using normal input patterns.     

Fuzzy Linear Programming with Interactive Uncertain Parameters

In this paper, we treat fuzzy linear programming problems with uncertain parameters whose ranges are specified as fuzzy polytopes. The problem is formulated based on fractile optimization model using a necessity measure. It is shown that the problem can be reduced to a semi-infinite linear programming problem and that a solution algorithm based on a relaxation procedure can be applied. A simple numerical example is given to illustrate the solution procedure. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Yb-doped YLiF4 laser crystal by the Czochralski method. Attempt of Yb energy level assignment and estimation of the laser potentiality

YLiF₄ (YLF) single crystals undoped and Yb³⁺-doped with different concentrations were grown by the Czochralski technique under CF₄ atmosphere. Detailed analysis of Yb³⁺-doped YLF spectroscopy were made to contribute to the determination of energy levels in this host. We are dealing with temperature and concentration dependences of both π and σ polarizations of the infrared (IR) absorption and emission spectra. Raman spectra were also used to give an attempt of interpretation of electronic and vibronic levels. The radiative energy transfer (self-trapping) and strong phonon–electron coupling make the assignment of Yb³⁺ energy levels difficult. Evaluation of the laser potentiality of this fluoride host is also presented.     

Czochralski growth of Yb doped oxyapatite for high power laser application

Ca₈(La,Yb)₂(PO₄)₆O₂ (Yb:CLPA) single crystals with the apatite-type structure could be grown from the melt using the Czochralski method. Grown crystal was 18 mm in diameter and 110 mm in length. It is transparent with slightly blue color. Neither visible inclusion nor crack was observed. Thermal conductivity of Yb:CLPA was calculated from the values of thermal diffusivity, heat capacity measurement and density. Luminescent characterization was carried out from the results of emission, absorption and Raman spectrum.     

Purification and characterization of a strong fibrinolytic enzyme (nattokinase) in the vegetable cheese natto, a popular soybean fermented food in Japan

A strong fibrinolytic enzyme (nattokinase) was purified from the vegetable cheese natto. Nattokinase was extracted from natto with saline and isolated by sequential use of hydrophobic chromatography on Butyl-Toyopearl, ion-exchange chromatography on CM-Toyopearl, and gel-filtration on Sephadex G-50. The isolated protein gave a single sharp band on SDS-PAGE either before or after reduction. The sequence, as determined by automated Edman degradation of the uncleaved molecule and its enzymatically derived peptide, consisted of a total 275 amino acid residues (M.W = 27,728) and exhibited a high homology with the subtilisins. The purified nattokinase digested not only fibrin but also several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was Suc-Ala-Ala-Pro-Phe-pNA for subtilisin. PMSF inhibited both the fibrinolytic activity and the amidolytic activity. The results indicate that nattokinase is a subtilisin-like serine protease.     

Left ventricular diastolic properties of hypertensive patients measured by pulsed tissue Doppler imaging

Examination of left ventricular (LV) diastolic dysfunction in hypertensive patients has been based on parameters obtained from the transmitral flow velocity during pulsed Doppler echocardiography. However, these parameters are affected by loading conditions. We evaluated LV diastolic function along the longitudinal and transverse axes by pulsed tissue Doppler imaging (TDI) in 50 hypertensive (HT) patients and 36 age-matched healthy volunteers (N). Transmitral flow velocity was recorded by pulsed Doppler echocardiography. LV posterior wall motion velocity along the longitudinal and transverse axes also was recorded by pulsed TDI. In both groups, peak early diastolic velocity of the LV posterior wall (Ew) along the transverse axis (N: 15.8+/-5.2 cm/s, HT: 12.2+/-4.4 cm/s) was higher than that along the longitudinal axis (N: 12.7+/-3.1 cm/s, HT: 9.5+/-3.3 cm/s). Peak atrial systolic velocity of the LV posterior wall (Aw) along the longitudinal axis (N: 9.1+/-1.8 cm/s, HT: 9.7 +/-2.6 cm/s) significantly exceeded that along the transverse axis (N: 8.0+/-2.2 cm/s, HT: 8.4+/-2.4 cm/s) in both groups. The Ews were lower and the Aws were higher along both axes in the patient group than in the control group. The time intervals from the aortic component of the second heart sound to the peak of the early diastolic wave (IIA-Ews) along both the transverse (N: 142+/-18 ms, HT: 154+/-19 ms) and longitudinal (N: 151 16 ms, HT: 162+/-20 ms) axes were longer in the patient group. In 29 patients, Ews along both axes correlated negatively (transverse: r = -0.80, P < .0001; longitudinal: r = -0.71, P < .0001) and IIA-Ews correlated positively (transverse: r = 0.81, P < .0001; longitudinal: r = 0.74, P < .001) with the time constant of the LV pressure decay during isovolumic diastole. The Aws along both axes in the 24 patients without pseudonormalization in transmitral flow velocity correlated positively (transverse: r = 0.60, P < .001; longitudinal: r = 0.74, P < .0001) with the LV end-diastolic pressure. In conclusion, LV relaxation and filling along the longitudinal and transverse axes were impaired in many patients with hypertension. Pulsed TDI was useful for evaluating LV diastolic dynamics in this disease.