Threshold voltage uniformity and characterization of microwaveperformance for GaAs/AlGaAs high electron-mobility transistors grown onSi substrates

We report on DC and microwave characteristics for high electron-mobility transistors (HEMT's) grown on Si substrates by metal-organic chemical vapor deposition (MOCVD). Threshold voltage (V _th) distribution in a 3-in wafer shows standard deviation of V_th (σV_th) of 36 mV with V_th of -2.41 V for depletion mode HEMT's/Si and σV_th of 31 mV with V_th of 0.01 V for enhancement mode, respectively. The evaluation of V_th in a 1.95×1.9 mm² area shows high uniformity for as-grown HEMT's/Si with σV_th of 9 mV for V_th of -0.10 V, which is comparable to that for HEMT's/GaAs. Comparing the V_th distribution pattern in the area with that for annealed HEMT's/Si, it is indicated that the high uniformity of V_th is obtained irrelevant of a number of the dislocations existing in the GaAs/Si. From microwave characteristic evaluation for HEMT's with a middle-(10~50 Ω·cm) and a high-(2000~6000 Ω·cm) resistivity Si substrate using a new equivalent circuit model, it is demonstrated that HEMT's/Si have the disadvantage for parasitic capacitances and resistances originated not from the substrate resistivity but from a conductive layer at the Si-GaAs interface. The parasitic parameters, especially the capacitances, can be overcome by the reduction of electrode areas for bonding pads and by the insertion of a dielectric layer under the electrode, which bring high cut-off frequency (f_T) and maximum frequency of operation (f_max) of 24 GHz for a gate length of 0.8 (μm). These results indicate that HEMT's/Si are sufficiently applicable for IC's and discrete devices and have a potential to be substituted for HEMT's/GaAs     

Smooth Scheduling under Variable Rates or the Analog-Digital Confinement Game

This work considers non-terminating scheduling problems in which a system of multiple resources serves clients having variable needs. The system has m identical resources and n clients; in each time slot each resource may serve at most one client; in each such slot t each client γ has a rate, a real number ρ _γ (t), that specifies his needs in this slot. The rates satisfy the restriction ∑ _γ ρ _γ (t)≤m for any slot t. Except of this restriction, the rates can vary in arbitrary fashion. (This contrasts most prior works in this area in which the rates of the clients are constant.) The schedule is required to be smooth as follows: a schedule is Δ -smooth if for all time intervals I the absolute difference between the amount of service received by each client γ to his nominal needs of ∑ _t∈I ρ _γ (t) is less than Δ. Our objective are online schedulers that produce Δ-smooth schedules where Δ is a small constant which is independent of m and n. Our paper constructs such schedulers; these are the first online Δ-smooth schedulers, with a constant Δ, for clients with arbitrarily variable rates in a single or multiple resource system. Furthermore, the paper also considers a non-concurrent environment in which there is an additional restriction that each client is served at most once in each time slot; it presents the first online smooth schedulers for variable rates under this restriction. The above non-concurrent restriction is crucial in some applications (e.g., CPU scheduling). It has been pointed out that this restriction “adds a surprising amount of difficulty” to the scheduling problem. However, this observation was never formalized and, of course, was never proved. Our paper formalizes and proves some aspects of this observation. Another contribution of this paper is the introduction of a complete information, two player game called the analog-digital confinement game. In such a game pebbles are located on the real line; the two players, the analog player and the digital player, take alternating turns and each one, in his turn, moves some of the pebbles; the digital player moves the pebbles backwards by discrete distances while the analog player moves the pebbles forward by analog distances; the aim of the analog player is to cause one pebble (or more) to escape a pre-defined real interval while the aim of the digital player is to confine the pebbles into the interval. We demonstrate that this game is a convenient framework to study the general question of how to approximate an analog process by a digital one. All the above scheduling results are established via this game. In this derivation, the pebbles represent the clients, the analog player generates the needs of the clients and the digital player generates the schedule. Dedicated to the memory of Professor Shimon Even for his inspiration and encouragement     

Advanced methods for displays and remote control of robots

An in-depth evaluation of the usability and situation awareness performance of different displays and destination controls of robots are presented. In two experiments we evaluate the way information is presented to the operator and assess different means for controlling the robot. Our study compares three types of displays: a “blocks” display, a HUD (head-up display), and a radar display, and two types of controls: touch screen and hand gestures. The HUD demonstrated better performance when compared to the blocks display and was perceived to have greater usability compared to the radar display. The HUD was also found to be more useful when the operation of the robot was more difficult, i.e., when using the hand-gesture method. The experiments also pointed to the importance of using a wide viewing angle to minimize distortion and for easier coping with the difficulties of locating objects in the field of view margins. The touch screen was found to be superior in terms of both objective performance and its perceived usability. No differences were found between the displays and the controllers in terms of situation awareness. This research sheds light on the preferred display type and controlling method for operating robots from a distance, making it easier to cope with the challenges of operating such systems.     

"Where similarity beats redundancy: The importance of context, higher order similarity, and response assignment": Correction to Eidels, Townsend, and Pomerantz (2008).

Reports an error in "Where similarity beats redundancy: The importance of context, higher order similarity, and response assignment" by Ami Eidels, James T. Townsend and James R. Pomerantz (Journal of Experimental Psychology: Human Perception and Performance, 2008[Dec], Vol 34[6], 1441-1463). The DOIs for the article and the supplemental materials were incorrectly listed. The correct DOIs are provided in the erratum. (The following abstract of the original article appeared in record 2008-16831-008.) People are especially efficient in processing certain visual stimuli such as human faces or good configurations. It has been suggested that topology and geometry play important roles in configural perception. Visual search is one area in which configurality seems to matter. When either of 2 target features leads to a correct response and the sequence includes trials in which either or both targets are present, the result is a redundant-target paradigm. It is common for such experiments to find faster performance with the double target than with either alone, something that is difficult to explain with ordinary serial models. This redundant-targets study uses figures that can be dissimilar in their topology and geometry and manipulates the stimulus set and the stimulus-response assignments. The authors found that the combination of higher order similarity (e.g., topological) among the features in the stimulus set and response assignment can effectively overpower or facilitate the redundant-target effect, depending on the exact nature of the former characteristics. Several reasonable models of redundant-targets performance are falsified. Parallel models with the potential for channel interactions are supported by the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New modifications of poly(vinyl alcohol)s and their applications

Poly(vinyl alcohol) (PV-OH), prepared from poly(viny) acetate), is used widely in many industries. Various grades have been produced, with different degree of polymerization and degree of hydrolysis. Recently, novel modified (PV-OH)s with anion, cation, silanol or hydrophobic groups have been studied and developed. They have new properties in addition to those of ordinary PV-OH and have new applications. The methods of modification and the characteristics and some applications of the modified polymers are described.     

Analytical modeling of energy efficiency in heterogeneous processors

Energy efficiency is increasingly critical for multi-core processors and many-core accelerators. In order to increase energy efficiency, chip manufacturers are developing heterogeneous CMP chips.     

A Study on the Distances of Small Mobile Robot Moves towards Infants

In recent years, it is remarkable that various robots are being developed, and the development of robot technology is beginning to be taken into an actual living space. There are still many questions that we will have to answer for the harmonization of living together with a robot. This study is focused on ＂the study of how to plan and design a living space in harmonizing with robots＂, and focused on the effects of infants （subjects） along with the distance between robots and themselves. The study is to seek for the minimum distance for the subjects who felt that ＂I do not want a robot to be any closer being approached to me＂. This experiment was conducted among 30 infants at the kindergarten, utilizing a small experimental robot. A small robot whose dimension is 120 mm （W） ×130 mm （D） × 70 mm （H）, approaching infants as is to see if it would make any differences to the infant＇s reactions.     

Cytotoxic components of bardanae fructus (goboshi)

Bardanae Furctus (Goboshi) extract showed potent in vitro cytotoxicity and in vivo antitumor activity against human hepatoma HepG2 cells and mouse sarcoma 180 cells, respectively. In this study, the cytotoxicities of four fractions and three major components (arctiin, arctigenin, and chlorogenic acid) isolated from Goboshi extract were examined. Arctiin and arctigenin, which were contained in the ethylacetate fraction and n-butanol fraction, respectively, showed strong cytotoxicity against HepG2 cells, but little toxicity against Chang liver cells. Chlorogenic acid isolated from the water fraction did not affect the viability of these cells. The cytotoxicity of arctigenin against Chang liver cells was markedly potentiated by treatment with glutathione (GSH) synthesis inhibitor, L-buthionine-(S,R)-sulfoximine (BSO). On the other hand, in HepG2 cells, the cytotoxicity of arctigenin was hardly changed by BSO. The cytotoxicity of arctigenin against HepG2 cells increased in an exposure-time dependent manner. These characteristics of arctigenin were similar to those of Goboshi extract, as previously observed. We therefore conclude that the principal cytotoxic components of Goboshi extract are arctiin and its aglycone arctigenin.     

Absence of germ-line mutations of the multiple endocrine neoplasia type 1 (MEN1) gene in familial pituitary adenoma in contrast to MEN1 in Japanese

Germ-line mutations of the MEN1 gene were analyzed in five cases of familial and four cases of sporadic multiple endocrine neoplasia type 1 (MEN-1), six cases in three independent pedigrees of familial pituitary adenoma without MEN-1, and three cases of familial isolated primary hyperparathyroidism (FIHP) in Japanese. Eight different types of germ-line mutations in all nine cases of MEN-1 were distributed in exons 2, 3, 7, and 10 and intron 7 of the MEN1 gene. Loss of heterozygosity (LOH) on 11q13 was detected in all nine tumors of these cases with microsatellite analysis. No germ-line mutation of the MEN1 gene was detected in three pedigrees of familial pituitary adenoma and three cases of FIHP. LOH on 11q13 was detected in two cases in one pedigree of familial pituitary adenoma, and one of them showed a heterozygous somatic mutation of the MEN1 gene. No LOH on 11q13 was detected in three cases of FIHP. Based on these, we conclude that the loss of function of menin is etiological for familial or sporadic MEN-1, but not for FIHP or most familial pituitary adenoma without MEN-1.