Shape optimization for a link mechanism

This paper presents a numerical solution for shape optimization problems for link mechanisms, such as a piston-crank mechanism. The dynamic behavior of a link mechanism is described by a differential-algebraic equation (DAE) system consisting of motion equations for each single body and constraints of linkages and rigid motions. In a shape optimization problem, the objective function to maximize is constructed from the external work done by a given external force, which agrees with the kinetic energy of the link mechanism, for an assigned time interval, and the total volume of all the links forms the constraint function. The Fréchet derivatives of these cost functions with respect to the domain variation, which we call the shape derivatives of these cost functions, are evaluated theoretically. A scheme to solve the shape optimization problem is presented using the H ¹ gradient method (the traction method) proposed by the authors as a reshaping algorithm, since it retains the smoothness of the boundary. A numerical example shows that reasonable shapes for each link such that mobility of the link mechanism is improved are obtained by this approach.     

A new optical elasticity resin for mobile LCD modules

Abstract— The display used in current cell phones has an air gap between the cover glass and the liquid‐crystal‐display (LCD) module to prevent the LCD glass from being damaged. Reflections at the boundaries of the air gap cause a reduction in the LCD luminance and contrast. To address this problem, a newly proposed LCD structure has been investigated. The “Super View Resin (SVR),” a transparent elastic resin which improves the shock resistance and visibility of the LCD, has been developed. Filling the air gap between the cover glass and LCD module with a refractive‐index‐matching resin solves the light‐reflection problem inherent in the use of a reinforced cover‐glass lens. Moreover, the elastic filler works as a damper, reducing any external shock, which prevents not only the cover glass and LCD module from being damaged, but also the glass from being shattered when it is broken.     

Three-dimensional medical image recognition of cancer of the liver by a revised radial basis function (RBF) neural network algorithm

In this study, we propose a revised radial basis function (RBF) neural network algorithm and apply this algorithm to computer-aided diagnosis (CAD) of the liver. First, the revised RBF neural network algorithm is applied to recognition of the liver regions, and the recognition results are compared with those obtained using the conventional RBF neural network and the conventional multilayered neural network trained using the back-propagation algorithm. It is shown that the revised RBF neural network is accurate, and is a useful method because the parameters are automatically determined. Then, the revised RBF neural network is applied to CAD of the liver cancer called hepatocellular carcinoma (HCC).     

Voronoi-based coverage control with anisotropic sensors and experimental case study

In this paper, we investigate coverage control problem for mobile sensor networks. The novelty is to consider an anisotropic sensor model whose performance depends not only on the distance but also on the orientation to a target point. By adapting Lloyd algorithm, a distributed control law is derived. Aside from coverage, we also show that the control law guarantees collision avoidance between the agents. The performance of the control laws is demonstrated through not only numerical simulation but also experiments on a mobile robot test bed.     

Refined mapping of a gene responsible for Fukuyama-type congenital muscular dystrophy: evidence for strong linkage disequilibrium

Fukuyama-type congenital muscular dystrophy (FCMD), the second most common form of childhood muscular dystrophy in Japan, is an autosomal recessive severe muscular dystrophy associated with an anomaly of the brain. After our initial mapping of the FCMD locus to chromosome 9q31-33, we further defined the locus within a region of approximately 5 cM between loci D9S127 and CA246, by homozygosity mapping in patients born to consanguineous marriages and by recombination analyses in other families. We also found evidence for strong linkage disequilibrium between FCMD and a polymorphic microsatellite marker, mfd220, which showed no recombination and a lod score of (Z) 17.49. A "111-bp" allele for the mfd220 locus was observed in 22 (34%) of 64 FCMD chromosomes, but it was present in only 1 of 120 normal chromosomes. This allelic association with FCMD was highly significant (chi 2 = 50.7; P < .0001). Hence, we suspect that the FCMD gene could lie within a few hundred kilobases of the mfd220 locus.     

Thermal conductivity and phonon scattering mechanisms in La#x2212;x#x2212;x#x2212;xMxCuO4

The thermal conductivity of high density La_2–xM_xCuO₄ (M=Ba, Sr) sintered materials was measured between 15K and 150K for the various concentrations of Ba and the phonon thermal conductivity was analyzed comparing with that of Nd_2–xCe_xCuO₄. The pretty large value for pure La₂CuO₄ was drastically diminished by substituting La by a small amount of Ba atoms especially at low temperatures. It was found that a new type of the phonon scattering center such as a two-level tunneling must be taken account of in order to explain the observed reduction.     

A 78-year-old man with young onset parkinsonism and sudden death

We report a right-handed 78-year-old man with early onset parkinsonism. The patient had an onset of micrographia at 23 years of the age in 1939. Seven years later he started to drag his right foot, and at 38 years of age, he walked with small steps with festination. Tremor was also present in his right hand. His daily life was independent as a otorhinolaryngologist. He visited our clinic on March 24, 1977 when he was mentally sound and showed mild parkinsonism consisting of masked face, stooped posture, small step gait, bradykinesia, and right side dominant rigidity and tremor. He showed good response to trihexyphenidyl and amantadine HCl. Two month later, he developed dyskinesia and some worsening of parkinsonism, and was admitted to our hospital for the first time. He was treated with 400 to 600 mg/day of levodopa/ carbidopa. He showed marked improvement, however, dyskinesia remained in his mouth. He was doing well until 77 years of age (June of 1993) when he developed hallucination and motor fluctuations. He was admitted again to our hospital on June 22, 1993. On admission, he was alert and appeared mentally sound. However, Hasegawa dementia scale was 18/30. Upward gaze was slightly restricted (3/5). Voice was somewhat small but no masking was noted. His posture was stooped and the gait was of small step. Dyskinesia was noted during walk. No rigidity nor tremor was noted. Deep tendon reflexes were lost but no sensory loss or motor weakness was noted. Routine laboratory studies were unremarkable. A cranial CT scan revealed only mild to moderate cortical atrophy. Motor and sensory conduction velocities were within normal limits, however, motor action potentials could not be obtained with stimulation to the right common peroneal nerve. He was treated with 600 mg/day of levodopa with carbidopa, 100 mg of amantadine HCl, 300 mg of Dops, and 25 mg of tiapride. He continued to show motor fluctuations, and was discharged on July 23, 1993. Since then his motor functions had become progressively worse with frequent falls, but he was still able to walk without support. On October 3 of 1994, he went to bed as usual. On the next morning, he was found dead in his bed at 9: 30. The patient was discussed in neurological CPC, and the chief discussant arrived at the conclusion that the patient had young-onset Parkinson's disease with Lewy bodies in the substantia nigra. Opinions were divided between Parkinson's disease and Lewy body negative young onset parkinsonism. Postmortem examination revealed obstruction of the trachea by aspirated foods, and the cause of death appeared to have been suffocation by the foods. Macroscopically, the external appearance of the brain was unremarkable except for slight frontal atrophy. The substantia nigra showed depigmentation in the lateral part, but the pigmentation of the medial part was well preserved. Upon histologic examination, the number of pigmented neurons in the dorsomedial part was well preserved. In the lateral part, pigmented neurons were well preserved in the dorsal area, however, in the ventral area, only non-pigmented neurons were seen; they appeared to be neurons in the pars reticulata. No gliosis was seen in any of the nigral areas. No Lewy bodies were seen in the remaining neurons. So-called immature neurons with rounded shape without neuromelanin could not be detected. The locus coeruleus neurons were well preserved. The putamen and the other basal ganglia structures were also intact. Slight myelin pallor was noted in the subcortical white matter, however, otherwise cerebral cortices were normal. The histology of this patient is unique in that only the ventrolateral part of the substantia nigra showed abnormal finding consisting of lack of pigmented neurons without gliosis. It is not clear whether the nigral change represents degeneration or a congenital "hypoplasia'. To our knowledge, such a unique pathology of the substantia nigra has not been reported in the literature. Our patient ma     

A control method with pheromone information for a transport system

Since the control methods of a transport system between processing machines are specialized for each layout of the system, it is difficult to design prompt schedules and control logic for new complicated systems, especially in cases of machine faults or restructuring the system to modify the layout. In this article, we describe a multiagent transport control system which utilizes pheromone information. Each element of the system acts as an agent and estimates the appropriate path and time to drive out the products using information obtained by communication with other elements as well as pheromone information deposited on the tracks of the products.     

A performance evaluation of disassembly systems with reverse blocking

For sustainable manufacturing, manufacturers should construct and design inverse manufacturing systems consisting of assembly and disassembly systems. The sorting process in the disassembly system is the first process of the whole inverse manufacturing system. Therefore, it can become a bottleneck and decrease the productivity of the whole inverse manufacturing systems.This study focuses on a disassembly system with reverse blocking in a sorting process [Yamada, T., & Matsui, M. (2003). Disassembly production systems and its design issues. Reprints of Japan Industrial Management Association, Spring meeting, Chofu, Japan, May, 144–145 (in Japanese)]. It generalizes the queuing model and discusses the performance of the disassembly system by mathematical and numerical analysis. First, the sorting process with reverse blocking is generally modeled as a queuing system. Next, the stationary state equations of the system are formulated, and the objective function is set as the throughput. Finally, the system performance is discussed by mathematical and numerical analysis in cases of a different number of stations and buffers, and also an example of the system design is shown and discussed in view of the busy rate, blocking probability and throughput.