Flexible Induction Heater Based on the Polymeric Thin Film for Local Thermotherapy

Local delivery of physical energy, such as heat, is promising for the treatment of target lesions without the unintended distribution of heat to other normal tissue. However, the heating device must be equipped with an external power source or strong magnetic field to operate the device, and many of them are too large to be placed inside the body. In this regard, wireless, lightweight, flexible electronics can be used for the miniaturization of implantable devices. In this study, a flexible induction heating (IH) device is reported that integrates inkjet-printed wirings and flexible polymeric thin films, specifically Au nanoink-based wirings (thickness: 1.5 µm) and a biodegradable poly(D, L-lactic acid) (PDLLA) thin film (thickness: 5 µm). A unique method of transferring the inkjet-printed Au nanoink wiring onto the PDLLA thin film realizes the integration of the following technical features in one device: biocompatible packaging, a printed IH system, and body conformability. The resulting thin-film IH device is successfully placed on a hepatic lobe of a beagle dog, which allows for a local increase in temperature of 7 °C after 1-min power feeding without tissue inflammation. The thin-film IH device is expected to provide minimally invasive thermotherapy when combined with endoscopic surgery.     

Feedforward operational stiffness modulation and external force estimation of planar robots equipped with variable stiffness actuators

A variable stiffness actuator (VSA) is considered a promising mechanism-based approach for realizing compliant robotic manipulators. By changing the stiffness of each joint, the robot can modulate the stiffness of the entire system to enhance safety and efficiency during physical interaction with other systems. This paper presents a feedforward method to modulate the operational stiffness of a parallel planar robot with multiple VSAs. A VSA utilizing a lever mechanism was developed, clearly presenting its mechanical design and kinematic model details. A computational model of joint-restoring torque was developed based on deformation measurements and hysteresis loop geometry to estimate the applied torque of each joint in real-time. An algorithm was proposed to compute the joint stiffness solution using the robot's kinematic model for modulating the operational stiffness of the parallel robot. Experiments were performed to evaluate the proposed method by comparing the performances of two DOF serial and parallel robot systems. The results demonstrated the capability of the VSA in both feedforward stiffness modulation and external force estimation.

     

Determining Server Locations in Server Migration Service to Minimize Monetary Penalty of Dynamic Server Migration

In this paper, we propose a new class of service called server migration service (SMS) to augment the existing IaaS (Infrastructure as a Service). SMS allows servers (server-side processes of a network application) to dynamically and automatically migrate as their clients (client-side processes of a network application) change their locations in order to reduce the total monetary penalty that the SMS provider pays to its SMS subscribers when failing to provide them with the guaranteed level of QoS. In this paper, we consider the monetary impact that arises from QoS degradation due to server migration and build an integer programming model to determine when and to which location servers should migrate to minimize the total monetary penalty incurred by the SMS provider. Numerical examples show that SMS achieves up to 96% lower total monetary penalty compared to that without server migration. Numerical examples also show that the integer programming model developed in this paper requires reasonable computation time under realistic parameter settings.     

DomainProfiler: toward accurate and early discovery of domain names abused in future

Domain names are at the base of today’s cyber-attacks. Attackers abuse the domain name system (DNS) to mystify their attack ecosystems; they systematically generate a huge volume of distinct domain names to make it infeasible for blacklisting approaches to keep up with newly generated malicious domain names. To solve this problem, we propose DomainProfiler for discovering malicious domain names that are likely to be abused in future. The key idea with our system is to exploit temporal variation patterns (TVPs) of domain names. The TVPs of domain names include information about how and when a domain name has been listed in legitimate/popular and/or malicious domain name lists. On the basis of this idea, our system actively collects historical DNS logs, analyzes their TVPs, and predicts whether a given domain name will be used for malicious purposes. Our evaluation revealed that DomainProfiler can predict malicious domain names 220 days beforehand with a true positive rate of 0.985. Moreover, we verified the effectiveness of our system in terms of the benefits from our TVPs and defense against cyber-attacks.     

Digestion of Ceramide 2-Aminoethylphosphonate,a Sphingolipid from the Jumbo Flying Squid <Emphasis Type="Italic">Dosidicus gigas</Emphasis>, in Mice

Ceramide 2-aminoethylphosphonate (CAEP), a sphingophosphonolipid containing a carbon–phosphorus bond, is frequently found in marine organisms and has a unique triene type of sphingoid base in its structure. CAEP has not been evaluated as a food ingredient, although it is generally contained in Mollusca organisms such as squids and shellfish, which are consumed worldwide. In this study, we aimed to elucidate the effects of CAEP as a food component by evaluating the digestion of CAEP extracted from the skin of the jumbo flying squid Dosidicus gigas. Our results revealed that dietary CAEP was digested to free sphingoid bases via ceramides by the mouse small intestinal mucosa. At pH 7.2, CAEP was hydrolyzed more rapidly than the major mammalian sphingolipid sphingomyelin; however, the hydrolysis of CAEP was similar to that of sphingomyelin at pH 9.0. Thus, the digestion of CAEP may be catalyzed by alkaline spingomyelinase and other enzymes. Our findings provide important insights into the digestion of the dietary sphingophosphonolipid CAEP in marine foods.     

Non-unitary master equation for the internal state of ions traversing solids

We present a new method describing the time development of the internal state of fast highly charged ions subject to collisions and to spontaneous radiative decay during transport through solids. Our method describes both the build-up of coherences and the decoherence of the open quantum system due to the interaction with its environment. The dynamics of the reduced density matrix is governed by a Lindblad master equation that can be solved by Monte Carlo sampling techniques. In practice, the standard Lindblad equation can be of limited value because it describes strictly unitary time transformations of the reduced density matrix. We have developed a generalized non-unitary Lindblad form (and its Monte Carlo implementation) for the evolution in finite subspaces in which the coupling to the complement is taken into account. We use the radiative decay of a free hydrogenic atom in vacuum as a simple test case. We present an application for Kr³⁵⁺ ions traversing carbon foils with varying thickness and compare our results with experiments.     

Questionnaire-based social research on opinions of Japanese visitors for communication robots at an exhibition

This paper reports the results of questionnaire-based research conducted at an exhibition of interactive humanoid robots that was held at the Osaka Science Museum, Japan. The aim of this exhibition was to investigate the feasibility of communication robots connected to a ubiquitous sensor network, under the assumption that these robots will be practically used in daily life in the not-so-distant future. More than 90,000 people visited the exhibition. A questionnaire was given to the visitors to explore their opinions of the robots. Statistical analysis was done on the data of 2,301 respondents. It was found that the visitors’ opinions varied according to age; younger visitors did not necessarily like the robots more than elderly visitors; positive evaluation of the robots did not necessarily conflict with negative evaluations such as anxiety; there was no gender difference; and there was almost no correlation between opinions and the length of time spent near the robots.     

Parameter estimation using simultaneous perturbation stochastic approximation

The simultaneous perturbation stochastic approximation (SPSA) is an extension of the Kiefer–Wolfowitz stochastic approximation algorithm. In SPSA, since all parameters are perturbed simultaneously, it is possible to modify parameters with only two measurements of an evaluation function regardless of the dimension of the parameter. We propose a parameter estimation algorithm using the SPSA. A convergence theorem for the proposed algorithm is shown. A simulation result also reveals the feasibility of the identification scheme proposed here. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 30–39, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20239     

On different modifications of the capillary model of penetration of inert liquid metals into porous refractories and their connection to the pore size distribution of the refractories

Different modifications to the classical capillary model of penetration of liquid metals into porous refractories are presented; (1) with capillaries having different radii, (2) with zigzag capillaries, and (3) with capillaries, having periodically changing capillary radius along the path of penetration. All the modified capillary models were checked against our experimental results of measuring the penetration of liquid mercury into three types of alumina refractories, having different microstructure and pore size distribution. The maximum penetration height was measured by X-ray radiography, as a function of applied outside pressure. The model with periodically changing capillary has been found to describe the experimental data satisfactorily. This model divides the process of penetration into two stages. During the first period of “pre-penetration,” the maximum penetration height changes very slowly (but not linearly) as the outside pressure is increased in the interval between the “minimum threshold pressure” and the “maximum threshold pressure.” In the second, “bulk penetration” period, appearing above the maximum threshold pressure, the maximum height of penetration increases rapidly with outside pressure, according to the classical capillary model of penetration. The three structural model parameters of the model (minimum pore radius, maximum pore radius, and period of pore structure) were connected with the measured pore size distribution curves of the refractories through semiempirical equations. As a result, our complex semiempirical model is able to predict penetration diagrams for any inert liquid metal into any refractory of a similar type.     

Effect of mechanical stress induced by etch-stop nitride: impact on deep-submicron transistor performance

This paper reports that process-induced mechanical stress affects the performance of short-channel MOSFETs, and focuses on the effect of a plasma-enhanced CVD nitride contact-etch-stop layer. The stress in the channel region induced by the nitride layer changes transconductance (G_m), thereby changing the device performance. When the nitride stress varies from +300 MPa (tensile) to −1.4 GPa (compressive), NMOSFET performance degrades by up to 8% and PMOSFET performance improves up to 7%. These changes are caused by the modulation of the electron/hole mobilities, so controlling process-induced stress and considering this mobility change in a precise transistor model are necessary for deep-submicron transistor design.