We derive physics-based formula of current-voltage characteristic for resonant tunneling diodes (RTDs) by using the Voigt function. The Voigt function describes the mixing condition of homogeneous and inhomogeneous broadenings of peak energy width in transmission probability, which is sensitively reflected to nonlinear negative differential resistance of RTDs. The obtained formula is applicable to the SPICE model of RTD without performing numerical integrals. We indicate validity of the formula by comparing to measured data for double-barrier and triple-barrier RTDs.

This paper introduces a new technique for electromagnetic immunity modeling of integrated circuits (ICs), compliant with industrial requirements and valid up to 3 GHz. A specific modeling flow is introduced, which makes it possible to predict the conducted immunity of an IC according to a given criterion, whatever its external environment. This methodology was validated through measurements performed on several devices.

This paper provides an investigation of power distribution network (PDN) performance by a full-wave prediction tool and by experimental measurements. A set of six real boards characterized by increasing complexity is considered in order to establish a solid base for behaviour understanding of printed circuit boards. How the growing complexity impacts on the board performance is investigated by measurements and by simulations. Strengths and weakness of PDN modeling by the full-wave software tool Microwave Studio are highlighted and discussed.

In this paper, an evaluation method for electromagnetic wave absorber with anisotropic reflection properties is discussed. Anisotropic absorber panels have an axis of anisotropy (principal axis). In order to specify the principal axis, the evaluation method based on the diagonalization of reflection coefficient matrix is used. Also, the permittivity of absorber materials is considered.

Memristor is drawing more and more attraction nowadays after HP Laboratory announced its invention. Since then many researchers are taking efforts to find its applications in various areas of the information technology. Among the important applications, one of the interesting issues is the research on memristor circuits. To put forward such research, there is an urgent demand to establish a memristor SPICE model, such that people could conduct SPICE simulation to obtain the performance of the memristor circuits under their investigation. This paper reports our efforts to meet the urgent demand. Based on the memristor device fabrication technology parameters, as well as the theoretical description on memristor, we first propose memristor SPICE models, then verify the effectiveness of the proposed models by applying it to some memristor circuits. Simulation results are satisfactory.

This paper proposes a topic-independent method for automatically scoring essay content. Unlike conventional topic-dependent methods, it predicts the human-assigned score of a given essay without training essays written to the same topic as the target essay. To achieve this, this paper introduces a new measure called MIDF that measures how important and relevant a word is in a given essay. The proposed method predicts the score relying on the distribution of MIDF. Surprisingly, experiments show that the proposed method achieves an accuracy of 0.848 and performs as well as or even better than conventional topic-dependent methods.

The selection of effective features is especially important in achieving highly accurate speech recognition. Although the mel-cepstrum is a popular and effective feature for speech recognition, it is still unclear that the filterbank adopted in the mel-cepstrum always produces the optimal performance regardless of the phonetic environment of any specific speech recognition task. In this paper, we propose a new cepstral domain feature extraction approach utilizing the entropic distance-based filterbank for highly accurate speech recognition. Experimental results showed that the cepstral features employing the proposed filterbank reduce the relative error by 31% for clean as well as noisy speech compared to the mel-cepstral features.

This paper proposes an improved method that uses a K-means method to effectively reduce the ringing artifacts in a color moving picture. To apply this improved K-method, we set the number of groups for the process to two (K=2) in the three dimensional R, G, B color space. We then improved the R, G, B color value of all of the pixels by moving the current R, G, B color value of each pixel to calculated center values, which reduced the ringing artifacts. The results were verified by calculating the overshoot and the slope of the light luminance around the edges of test images that had been processed by the new algorithm. We then compared the calculated results with the overshoot and slope of the light luminance of the unprocessed image.

This paper studies reflection and transmission of a TE plane wave from a two-dimensional random slab with statistically anisotropic fluctuation by means of the stochastic functional approach. By starting with a representation of the random wavefield presented in the previous paper [IEICE Trans. Electron., vol.E92-C, no.1, pp.77-84, Jan. 2009], a solution algorithm of the multiple renormalized mass operator is newly shown even for anisotropic fluctuation. The multiple renormalized mass operator, the first-order incoherent scattering cross section and the optical theorem are numerically calculated and illustrated in figures. The relation between statistical properties and anisotropic fluctuation is discussed.

A variety of ZnO belt-like structures were synthesized by the heat treatment of ZnS substrates with Ga droplets in the air, and their morphological and structural properties were investigated. Three types of ZnO belts with flat surfaces of (20), (100) and (23) were obtained. As comparison, the ZnO crystal growth was examined by the thermal oxidation of ZnS only. These results highlight the promise of the heat treatment with Ga in the synthesis of oxide nanostructures.

In this paper, the issue of carrier frequency offset (CFO) compensation in interleaved orthogonal frequency division multiple access (OFDMA) uplink system is investigated. To mitigate the effect of multiple access interference (MAI) caused by CFOs of different users, a new parallel interference cancellation (PIC) compensation algorithm is proposed. This scheme uses minimum mean square error (MMSE) criterion to obtain the estimation of interference users, then circular convolutions are employed to restore MAI and compensate CFO. To tackle the complexity problem of circular convolutions, an efficient MAI restoration and cancellation method is developed. Simulations illustrate the good performance and low computational complexity of the proposed algorithm.

An ICI (Inter-Cell Interference) mitigation algorithm for exploiting macroscopic diversity for an up-link OFDMA (Orthogonal Frequency Division Multiple Access) system is proposed. To reduce the influence of carrier collision, the order of resource allocation is coordinated based on the location of each MS (Mobile Station) and the associated carrier group. This consideration significantly reduces ICI and enhances throughput at the boundary region.

A square-root (SR) algorithm, an SR architecture and a leakage current reduction circuit were developed to reduce dynamic power (PAT) and leakage power (PST), while maintaining the speed of a CMOS SR circuit. Using these techniques, a 90-nm CMOS LSI was fabricated. The PAT of the new SR circuit at a clock frequency (fc) of 490 MHz and a supply voltage (VDD) of 0.75 V was 104.1 µW, i.e., 21.6% that (482.3 µW) of a conventional SR circuit. The PST of the new SR circuit was markedly reduced to 19.51 nW, which was only 1.69% that (1,153 nW) of the conventional SR circuit.

The authors present an accurate analysis for multicode code division multiple access (CDMA) systems equipped with a multipath interference canceler (MPIC) over multipath fading channels. This letter verifies that the previous analysis has used the additional Gaussian approximation (AGA) for multipath interferences so that there is the performance mismatch between the previous analysis and simulations. Furthermore, it is confirmed that the proposed analysis, which does not use AGA, provides an analytical bound.

This letter presents an analytical method for 64-QAM CDMA systems equipped with a multipath interference canceler (MPIC) over multipath fading channels. Numerical results obtained from the proposed analysis indicate that an MPIC is required in order to mitigate the effects of multipath interference and to effectively increase the system capacity.

We propose an enhanced method for translating Topic Maps to RDF/RDF Schema, to realize the Semantic Web. A critical issue for the Semantic Web is to efficiently and precisely describe Web information resources, i.e., Web metadata. Two representative standards, Topic Maps and RDF have been used for Web metadata. RDF-based standardization and implementation of the Semantic Web have been actively performed. Since the Semantic Web must accept and understand all Web information resources that are represented with the other methods, Topic Maps-to-RDF translation has become an issue. Even though many Topic Maps to RDF translation methods have been devised, they still have several problems (e.g. semantic loss, complex expression, etc.). Our translation method provides an improved solution to these problems. This method shows lower semantic loss than the previous methods due to extract both explicit semantics and implicit semantics. Compared to the previous methods, our method reduces the encoding complexity of resulting RDF. In addition, in terms of reversibility, the proposed method regenerates all Topic Maps constructs in an original source when is reverse translated.

Conveying information about who, what, when and where is a primary purpose of some genres of documents, typically news articles. Statistical models that capture dependencies between named entities and topics can play an important role in handling such information. Although some relationships between who and where should be mentioned in such a document, no statistical topic models explicitly address the textual interactions between a who-entity and a where-entity. This paper presents a statistical model that directly captures the dependencies between an arbitrary number of word types, such as who-entities, where-entities and topics, mentioned in each document. We show that this multitype topic model performs better at making predictions on entity networks, in which each vertex represents an entity and each edge weight represents how a pair of entities at the incident vertices is closely related, through our experiments on predictions of who-entities and links between them. We also demonstrate the scale-free property in the weighted networks of entities extracted from written mentions.

Since participants at both end of the communication channel must share common pictogram interpretation to communicate, the pictogram selection task must consider both participants' pictogram interpretations. Pictogram interpretation, however, can be ambiguous. To assist the selection of pictograms more likely to be interpreted as intended, we propose a categorical semantic relevance measure which calculates how relevant a pictogram is to a given interpretation in terms of a given category. The proposed measure defines similarity measurement and probability of interpretation words using pictogram interpretations and frequencies gathered from a web survey. Moreover, the proposed measure is applied to categorized pictogram interpretations to enhance pictogram retrieval performance. Five pictogram categories used for categorizing pictogram interpretations are defined based on the five first-level classifications defined in the Concept Dictionary of the EDR Electronic Dictionary. Retrieval performances among not-categorized interpretations, categorized interpretations, and categorized and weighted interpretations using semantic relevance measure were compared, and the categorized semantic relevance approaches showed more stable performances than the not-categorized approach.

We propose to integrate a single lens on top of multiple OLEDs. Angular distribution of the light emitted from the lens surface is altered by turning on the OLEDs selectively. We can use such a light source as a backlight for a liquid crystal display to switch its viewing angle range and/or to display multiple images in different directions. Pixel-level integration would allow one to construct an OLED display with a similar emission angle control.

The pickup and delivery problem (PDP) asks to find a set of vehicles that serve a given set of requests with the minimum travel cost, where each request consists of a pickup point, a delivery point and a load (the quantity to be delivered from the pickup point to the delivery point). In the pickup and delivery problem with transfer (PDPT), for each request, its load picked up at the pickup point is allowed to be dropped at a transshipment point before it is picked up again and delivered to the delivery point by another vehicle. This paper analyzes the maximum travel cost that can be saved by introducing a transshipment point to the pickup and delivery problem (PDP). We show that the bounds are in proportion to square root of the number of cycles in an optimal PDPT solution and also square root of the number of requests. We furthermore present an instance that the bound is the tight for a special case.