GMDH utilizing BDS with insufficient modelling data

It has been pointed out that the group method of data handling algorithm has a disadvantage that predicts an abnormal result in the event of shortage of modelling data. This paper presents a method of modelling that avoids the emergence of abnormal predicted values. For estimation of partial polynomial parameters, a bad data suppression estimator is employed. It is based on a non-quadratic cost function that reduces to the weighted least squares estimator in the absence of bad data. Real data are used to illustrate that this method prevents abnormal results.     

钢铁中多元夹杂物颗粒的三维评估

为了从钢铁中提取各种夹杂物颗粒,考察了采用无水电解质的恒电位和恒电流的提取方法。结果认为,4%的MS［4 % （V/V）甲基水杨酸-1 % （m/V） 水杨酸-1 %（ m/V） 四甲基氯化铵-甲醇）和10%AA（10 %(V/V)乙酰丙酮-1 % （m/V）四甲基氯化铵-甲醇］电解质溶液适用于提取钢铁中夹杂物TiO_{x和TiAl2O5。尽管这些电解提取法可以提取化学性能不稳定的夹杂物颗粒,然而,因为对夹杂物的观察是在萃取完成后于一个滤膜中进行,因此无法确定金属中每种夹杂物的具体位置。为了确定金属中夹杂物的具体位置,将卤-醇的光蚀刻方法用于以Ti和Al除氧的钢样品表面附近出现的夹杂颗粒,使用扫描电子显微技术和俄歇电子能谱（AES）对精细夹杂物颗粒形貌、尺寸和元素的偏析进行评估,不过卤醇却和钢铁中的金属钛和金属铝发生还原反应。对微小夹杂物颗粒的成分的形态、分离进行估测,然后,使用一种低加速能-扫描电子显微技术和俄歇电子能谱（AES）对用聚焦离子束制备微小夹杂物颗粒截面上元素的微观偏析进行评定。在这些研究结果基础上讨论了多元夹杂物颗粒的形成机理。}     

用光学纹影摄影术观察分析定容燃烧室内氢燃料的燃烧过程

论述了采用纹影摄影术和高速摄影法观察分析氢气和空气预混合燃料在定容燃烧室内的火花点火燃烧过程,定性地分析了预混合氢气燃料的火焰形态和变化过程,以及燃烧室内的初始压力和空燃比对火焰传播速度及其燃烧压力的影响,通过采用纹影摄影术方法,初步揭示了预混合氢气燃料在定容燃烧室内燃烧时火焰初期紊流产生的机理,以及由开始的层流状火焰发展到湍流状火焰的过程,研究结果表明,预混合氢气燃料燃烧的火焰传播速度及燃烧压力明显地受燃烧室内的初始压力和空燃比的影响。     

Prediction by dual mode GMDH

The effect of applying the dual mode group method of data handling (GMDH) to the prediction of social systems is investigated. In order to suppress overfitting, a method is adopted whereby the predictional model is automatically changed to the uni-input basic function mode from the original GMDH basic function mode at a sign of overfitting. Two examples show the effectiveness of this method.     

Jib crane control to suppress load swing

The simulation of a jib crane control strategy is reported which transfers a load under the condition of suppressing the load swing both in the transfer process and at the objective position, making the transfer time as short as possible. A non-linear dynamic equation of the load in a jib crane motion is derived. By linearizing the equation and giving a cost function of the second order, the control problem becomes LQ-type with control constraint u. Computer simulations show that this control strategy is able to suppress the load swing by the extending or shrinking motion of the boom.     

An analysis of land use/cover change in Indonesia

The phenomena of land use/ change were evaluated by using a remote sensing approach in a case study in Yogyakarta, Indonesia. The index of changes, which was calculated by the superimposition of land use/ images of 1972, 1984, and land use maps of 1990, were introduced to analyse the pattern of change in the area. The results demonstrated that the pattern of land use/ change in the study area was that of paddy coverage to open/ land to settlement. The annual growth ratios of new settlements to absorb paddy coverage, mixed vegetation, and open/ land were 16 per cent, 20 per cent, and 64 per cent respectively. The larger the percentage of the paddy coverage, the higher the tendency for settlement growth to absorb the paddy coverage, and the larger the percentage of open/ land, the higher the tendency for settlement growth to absorb open/ land. Settlement growth had a high correlation with road accessibility. The highest settlement growth was distributed mostly in suburban areas between 200 and 400 m from secondary roads. Without intelligent intervention by the government and public awareness, the loss of these agricultural land cannot be stopped and will jeopardize the local and regional economy.     

Improved dual mode GMDH with automatic switch

This paper proposes a stable dual mode GMDH. In each layer, two types of functions are prepared and compared with each other. The output of the model is given by the superior function, which is automatically selected according to the criterion proposed in this paper. Two real social systems arc applied to check the effectiveness of this method. A modelling interval longer than the period of the real system suppresses large predictionsl errors.     

Lactic Fermentation Effects on Preservative Qualities of Dendeng Giling

Model “Dendeng giling”, Indonesian non fermented dried beef, was prepared after fermentation with Lactobacillus plantarum as starter and compared with control without starter culture. Inoculated sample was fermented at 30°C 16 hr, Lactobacillus grew from 10⁶ to 10⁸, pH went from 5.71 to 5.2. Micrococcus, Gram-negative bacteria, Pseudomonas, Staphylococcus, and Escherichia coli were inhibited by 98.3%, 77%, 93%, 96% and 77% after fermentation 16 hr. Inoculated samples were tested for inhibiting VBN and TBA value, dissipating residual nitrite and development of redness. Lower pH caused faster drying at 50°C and reduced water activity. The combination of low pH and water activity made possible improvement of preservative quality.     

Free Amino Acids and Related Compounds in Seeds and Sprouts of Winged Bean Psophocarpus tetragonolobus (L.) DC)

Free amino acids and related compounds in the nonprotein nitrogen (NPN) fraction of winged bean seeds and sprouts were quantitatively determined. The proportion of NPN to total nitrogen was low in the seeds (9%) and in the cotyledons of the sprouts (11%), and relatively high in the epicotyls of the sprouts (54%). About 6% and 40% NPN were attributable to free amino acid nitrogen in the seeds and the sprouts, respectively. The free amino acid profile of seeds was characterized by the presence of sizable amounts of γ-L-glutamyl-L-tyrosine and γ-L-glutamyl-L-phenylalanine, indicating similarities to that of soybean seeds. Accumulation of free amino acids, particularly nonprotein amino acids such as α-aminoadipic acid and γ-aminobutyric acid, were demonstrated in the sprouts. No canavanine was detected in either seeds or sprouts.     

Transient Electric Field Analysis in Consideration of the Electric Field Dependence of Resistivity in the Converter Transformer

In this paper, values of the electric field in the pressboard and oil during the polarity reversal test of the converter transformer were calculated with transient analysis. First, we confirmed the accuracy of the nonlinear analysis in the model test. Next, we carried out nonlinear transient electric field analysis for polarity reversal test of the converter transformer. In the results, when the applied time of dc voltage before the polarity reversal is 360 min, the values of the electric field of oil area are the same as when it is 90 min. Although, the electric field in the pressboard becomes higher in response to the applied time dc voltage, it does not cause a problem on the insulation. Because withstand voltage of pressboard is very high. In the results, the correlation between the applied time of dc voltage before the polarity reversal and the withstand voltage of transformer is considered low. This result can be applied to the design of the converter transformer.