Mitsuhiro Kimura

Economic analysis of software release problems with warranty cost and reliability requirement

Abstract We discuss optimal software release problems which consider both a present value and a warranty period (in the operational phase) during which the developer has to pay the cost for fixing any faults detected. It is very important with respect to software development management that we solve an optimal software testing time by integrating the total expected testing cost and the reliability requirement. We apply a nonhomogeneous Poisson process model to the formulation of a software cost model and analyze three typical cases of the cost model. Moreover, we derive several optimal release polices. Finally, numerical examples are shown to illustrate the results of the optimal policies.

Deafferentation-induced c-fos gene expression in subthalamic nucleus and substantia nigra reticulata is reduced by non-NMDA receptor antagonist

Molecular events underlying the mechanism by which brain injury elicits delayed transneuronal degeneration of neurons remote from the site of initial injury are not well understood. In rats, acute injury of the caudate nucleus (CN) and globus pallidus (GP) by local injection of excitotoxic ibotenic acid (IA) or by transient forebrain ischemia resulted in delayed cell death of neurons in the substantia nigra reticulata (SNr). To elucidate the involvement of glutamate receptor mediated hyperactivity of neurons produced by loss of inhibitory inputs in this delayed degeneration of SNr neurons, the region-specific expression of an immediate early gene, c-fos, and the effect of glutamate receptor antagonists on the c-fos expression were examined by using immunocytochemical and in situ hybridization analysis. Following unilateral IA-injection into the CN and GP, a robust expression of c-fos mRNA and Fos protein was induced specifically in neurons of both subthalamic nucleus (STN) and SNr deafferented by the IA-lesions 36 h after IA-injection. The delayed expression of Fos-protein in SNr neurons lasted for 48 h longer than that in STN neurons. Following unilateral IA-injection confined to the CN, an intense but short-term expression of Fos-protein was exhibited only in neurons of the deafferented SNr. c-fos mRNA and Fos protein were not expressed in neurons of the substantia nigra compacta at any time points examined. The induction of c-fos mRNA and Fos protein in neurons of the STN and SNr following IA-lesions of the CN and GP was reduced markedly by non-NMDA receptor antagonist (GYKI52466), but not by NMDA receptor antagonist (MK-801). The region-specific c-fos expression implies that deprivation of inhibitory afferents (disinhibition) due to destruction of presynaptic neurons can induce increased activity of postsynaptic neurons. The effect of GYKI52466 on the c-fos gene expression in neurons of the deafferented STN and SNr suggests that activation of non-NMDA receptors may be involved in a pathophysiological cascade for the transneuronal degeneration of SNr neurons.

Protective effect of a low dose of colchicine on the delayed cell death of hippocampal CA1 neurons following transient forebrain ischemia.

Transient forebrain ischemia in rats preferentially causes neuron death in the striatum and hippocampal CA1 area. Prior injection of a low dose (1 microl) of colchicine (1 microM) into the unilateral hippocampus prevented ischemic damage of CA1 neurons in both hippocampal hemispheres, whereas no protection against ischemic damage was seen in the striatum. These results suggest that disconnection of hippocampal neurons by blockade of axoplasmic transport with colchicine specifically protects ischemic damage of CA1 neurons.

Software reliability assessment tool based on object-oriented analysis and its application

In general, the software testing-efforts which are spent in large-scale software development account for a half of the total amount of the development effort. Therefore, the management of fault-detection and fault-correction activities in the testing phase is very important to efficiently and economically develop a highly-reliable software product. In this paper, a software management tool which aids the quality/reliability assessment and testing-progress control in the testing phase is developed. This tool consists of several sub-systems that analyze software fault-detection data and assess software quality/reliability and testing-progress based on adopted software reliability growth models. Also, we use JAVA language to implement the tool. The JAVA language is widely known as an object-oriented and platform-free programming language. These characteristics are suitable for constructing our tool, because the tool will be revised to adopt new software reliability growth models and/or new testing-control techniques.

A novel membrane protein #123 specifically expressed in olfactory sensory neurons

P3-i13 A novel membrane protein #123 specifically expressed in olfactory sensory neurons Tomomi Kaneko-Goto 1 , Yuki Sato 1, Sayako Katada 1,2, Sei-ichi Yoshihara 1, Atsushi Nishiyori 1, Mitsuhiro Kimura 1, Kazushige Touhara 2, Randall R. Reed 3, Yoshihiro Yoshihara 1 1 Lab. Neurobiology of Synapse, RIKEN BSI, Wako, Japan 2 Grad. School of Agri Life Sci, University of Tokyo, Tokyo 3 Center for Sensory Biology, Johns Hopkins Sch. of Med, MD, USA

Optimal initial production control period based on a quality growth model

The initial production phase of new products or the initial installation phase of new manufacturing facilities is often unstable because of inexperienced workers and many defective products. An initial production process control, in which the defects in design, production technologies and products are fully fixed and removed, is switched to a normal process control whenever it is ready for actual mass production. This paper discusses a method of deciding the optimal initial production control period, based on a quality growth model. It is determined by the number of products with the minimum expected total quality control cost. Finally a penalty cost due to unattainable loss to the quality goal is introduced in the quality control cost: the realized stabilization level of the initial production process control is lower than the original quality objective. Numerical illustrations of the optimal policy are also presented. Copyright

Developmental changes of drebrin subcellular localization within neurons

Drebrin, an actin binding protein, has been reported to exist richly in dendritic spines both in adult brain and in 3 week-old primary cultured neurons (Hayashi et al, in submission). In the present study. we investigated the developmental changes of drebrin expression and subcellular localization in neurons using a primary culture of cortical neurons. Cerebral cortical neurons of 20-day-old fetal rats were dissociated and plated on polyethlenimine-coated cover slips in minimum essential medium supplemented with glial conditioned medium. After fixation with 3.7’5 pamformaldehyde, cells were immunostained and observed with confocal microscopy. In culture from one to three days old. drebrin w’as relatively abundant in the cortical cytoplasm of neurons and neurites, while drebrin can hardly be observed in GFAP-positively stamed glia or fibroblasts with vvell developed stress fibers. After 2 weeks in vitro, strong drebrin immunoreactivity was observed to be discontinuously distributed along the neurites and within the dendritic spines.

1334 Protective effect of colchicine on the delayed neuronal cell death of the hippocampal neurons by transient forebrain ischemia in rats

Recent evidence suggests that the endogeneous excitatory amino acid neurotransmitter glutamate might play an important role in the pathogenesis of hypoxic or ischemic neuronal injury in the CNS. Adenosine also released during hypoxia. Therefor, we examine the effects of adenosine on cytotoxicity induced by hypoxia and hypoglycemia by using rat cultured cortical neurons. A 30 90 min period of oxygen and glucose deprivation induced widespread degeneration of cultured cortical neurons. Hypoxic cortical neuronal injury was ameriolated by adenosine, N6-cyclohexyladenosine (CHA, A1 receptor agonist), CGS-21680, an AZA receptor agonist, and MK-801. When cultures exposed to hypoxia and hypoglycemia, extracellular adenosine levels were markedly increased. Moreover, hypoxic neuronal injury was deteriorated by &cyclopentyltheophyIline (CPT, AI receptor antagonist) and KF-17114, an AZ receptor antagonist. Brief glutamate exposure to the cell induced delayed neuronal death. Adenosine and CGS-21680 were effective in protecting cultured cortical neurons from glutamate cytotoxicity. By contrast, CHA did not affect the cytotoxicity induced by glutamate. These results indicate that adenosine has dual protective processes against hypoxic neuronal injury. One is presynaptic action via At receptors and another is postsynaptic action via A?receptors.

Quality assessment models for initial production process control based on stochastic differential equations

Abstract It is of great importance to assess an initial production process prior to the regular mass-production. For this purpose, many statistical methods have been proposed for practical use. In this paper, we propose two stochastic models for an assessment method of the initial production process control: a Markov process model and a Markov approximation model. These models are continuous state space models and formulated by applying mathematical techniques of stochastic differential equations. Based on each model, we derive several quantitative assessment measures for initial production process control.