Adaptive disk scheduling with workload-dependent anticipation intervals

Anticipatory scheduling (AS) of I/O requests has become a viable choice for block-device schedulers in open-source OS-kernels as prior work has established its superiority over traditional disk-scheduling policies. An AS-scheduler selectively stalls the block-device right after servicing a request in hope that a new request for a nearby sector will be soon posted. Clearly, this decision may introduce delays if the anticipated I/O does not arrive on time. In this paper, we build on the success of the AS and propose an approach that minimizes the overhead of unsuccessful anticipations. Our suggested approach termed workload-dependent anticipation scheduling (WAS), determines the length of every anticipation period in an on-line fashion in order to reduce penalties by taking into account the evolving spatio-temporal characteristics of running processes as well as properties of the underlying computing system. We harvest the spatio-temporal features of individual processes and employ a system-wide process classification scheme that is re-calibrated on the fly. The resulting classification enables the disk scheduler to make informed decisions and vary the anticipation interval accordingly, on a per-process basis. We have implemented and incorporated WAS into the current Linux kernel. Through experimentation with a wide range of diverse workloads, we demonstrate WAS benefits and establish reduction of penalties over other AS-scheduler implementations.     

Conventional vehicle display panels: the drivers' operative images and directions for their redesign

The proliferation of new displays in modern vehicles sets the challenge to revisit the design of the conventional display units, toward more simplified appearance. The present study aims to evaluate the usefulness of the information provided to the drivers by the conventional vehicle display units, in order to trace directions that would lead to a simplification of the future display panels. Based on the concept of operative images, two working hypotheses were formulated: (i) the experienced drivers have developed an operative image-reference (OI-R) for the display panel of their own vehicle(s), reflecting the relative importance they attribute to the information emitted by the various displays of the panel, and (ii) the experienced drivers' drawings of the display panel of their own vehicle will be guided by their OI-R for it - providing therefore traces of the content of their OI-R, while the less experienced drivers' drawings will be closer to the actual display panel of their own vehicle. The method of drawing from memory was used to obtain traces of the operative images of both experienced and less experienced non-professional drivers. The obtained 335 drawings were compared to the actual display panels, as to their overall resemblance and to specific features. The results of the data analysis are in accordance to our working hypotheses. Considering the main features of the experienced drivers' OI-R, directions for the simplification of the appearance of conventional display units are proposed.     

Handwritten document image segmentation into text lines and words

Two novel approaches to extract text lines and words from handwritten document are presented. The line segmentation algorithm is based on locating the optimal succession of text and gap areas within vertical zones by applying Viterbi algorithm. Then, a text-line separator drawing technique is applied and finally the connected components are assigned to text lines. Word segmentation is based on a gap metric that exploits the objective function of a soft-margin linear SVM that separates successive connected components. The algorithms tested on the benchmarking datasets of ICDAR07 handwriting segmentation contest and outperformed the participating algorithms.     

A model-driven software engineering workflow and tool architecture for servitised manufacturing

Modern manufacturing businesses increasingly engage in servitisation, by offering advanced services along with physical products, and creating “product–service systems”. Information Technology infrastructures, and especially software, are a critical part of modern service provision. However, software development in this context has not been investigated and there are no development methods or tools specifically adapted to the task of creating software for servitised businesses in general, or manufacturing in particular. In this paper, we define the requirements for software engineering in servitised manufacturing. Based on these, we describe a model-driven software engineering workflow for servitised manufacturing, supporting both structural and behavioural modelling of the service system. Furthermore, we elaborate on the architecture of an appropriate model-driven Integrated Development Environment (IDE). The proposed workflow and a prototype implementation of the IDE were evaluated in a set of industrial pilots, demonstrating improved communication and collaboration between participants in the software engineering process.     

Multispectral image fusion for improved RGB representation based on perceptual attributes

A pixel‐level fusion technique for RGB representation of multispectral images is proposed. The technique results in highly correlated RGB components, a fact which occurs in natural colour images and is strictly related to the colour perception attributes of the human eye. Accordingly, specific properties for the covariance matrix of the final RGB image are demanded. Mutual information is employed as an objective criterion for quality refinement. The method provides dimensionality reduction, while the resulting RGB colour image is perceptually of high quality. Comparisons with existing techniques are carried out using both subjective and objective measures.     

ASTERIX: towards a scalable,semistructured data platform for evolving-world models

ASTERIX is a new data-intensive storage and computing platform project spanning UC Irvine, UC Riverside, and UC San Diego. In this paper we provide an overview of the ASTERIX project, starting with its main goal—the storage and analysis of data pertaining to evolving-world models. We describe the requirements and associated challenges, and explain how the project is addressing them. We provide a technical overview of ASTERIX, covering its architecture, its user model for data and queries, and its approach to scalable query processing and data management. ASTERIX utilizes a new scalable runtime computational platform called Hyracks that is also discussed at an overview level; we have recently made Hyracks available in open source for use by other interested parties. We also relate our work on ASTERIX to the current state of the art and describe the research challenges that we are currently tackling as well as those that lie ahead.     

Should I stay or should I go? The moderating effect of self-image congruity and trust on social networking continued use

Recent reports show that although users of large online social networks (such as Facebook) score low in terms of satisfaction, they manage to retain, or even increase, their user base. This study sheds an exploratory light on the reuse behaviour of online social network services (SNS). Specifically, we investigate the moderating effects of self-image congruity and trust on the relationship between satisfaction and continuance to use online SNS. To capture post-adoption behaviour of SNS users, we employ the expectation–confirmation model as a core structure for our theoretical model. The model is empirically tested using survey data collected from 288 Facebook users. Results reveal a possible trend suggesting that users perceiving a high match of the SNS with their self-image will be more loyal even if they experience low satisfaction levels. The same trend has been extracted for trust and its moderating effect on the relationship between satisfaction and usage continuance intention. This paper concludes with a discussion on the theoretical and practical implications of our findings.     

Design and implementation of a VoiceXML-driven wiki application for assistive environments on the web

In this paper, we describe the design and implementation of an audio wiki application accessible via both the Public Switched Telephone Network and the Internet. The application exploits mature World Wide Web Consortium standards, such as VoiceXML, Speech Synthesis Markup Language, and Speech Recognition Grammar Specification toward achieving our goals. The purpose of such an application is to assist visually impaired, technologically uneducated, and underprivileged people in accessing information originally intended to be accessed visually via a personal computer (PC). Users may access wiki content via fixed or mobile phones, or via a PC using a Web Browser or a Voice over IP service. This feature promotes pervasiveness to collaboratively created content to an extremely large population, i.e., those who simply own a telephone line.     

A numerical algorithm for the diffusion equation using 3D FEM and the Arnoldi method

In this paper we introduce a new computational method for solving the diffusion equation. In particular, we construct a generalized state-space system and compute the impulse response of an equivalent truncated state-space system. In this effort, we use a 3D finite element method (FEM) to obtain the state-space system. We then use the Arnoldi iteration to approximate the state impulse response by projecting on the dominant controllable subspace. The idea exploited here is the approximation of the impulse response of the linear system. We study the homogeneous and heterogeneous cases and discuss the approximation error. Finally, we compare our computational results to our experimental setup.This research was supported by the Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita 434, Japan.     

A New Low Latency Parallel FIR Filter Scheme

A new array type parallel scheme for an FIR digital filter is presented in this paper. The proposed scheme is based on the structure of the carry-save array multiplier where each cell implements the computation of an FIR filter at the bit-level. This structure leads to latency independent of the number of the filter taps. The proposed scheme is pipelined at the bit-level, is systolic at the cell-level and requires less hardware than other schemes based on discrete multipliers.Paraskevas Kalivas received his Diploma and Ph.D. degree in electrical and computer engineering from the National Technical University of Athens, Greece, in 1990 and 2000 respectively.His research interests include computer arithmetic and efficient realization of arithmetic circuits and digital filters.Vassilis Vassilakis received his Diploma in electrical and computer engineering from NationalTechnical University of Athens, Greece, in 1997. He isworking toward the Ph.D. degree in electrical engineering at National Technical University of Athens.His research interests include efficient circuit implemenation of DSP algorithms and java processor architectures.Chris Meletis received his Diploma in electrical and computer engineering from National Technical University of Athens in 1997. Currently, he is working toward the Ph.D. degree in electrical engineering at National Technical University of Athens.His research interests include multirate filter banks, digital filter design and their efficient realization.Kiamal Z. Pekmestzi received his Diploma in electrical engineering from the National Technical University of Athens, Greece, in 1975. From 1975 to 1981, he was a research fellow in the Electronics Department of the Nuclear Research Center Demokritos. He received his Ph.D. in electrical engineering from the University of Patras, Greece, in 1981.From 1983 to 1985, he was a professor at the Higher School of Electronics in Athens. Since 1985, he has been with the National Technical University of Athens, where he is currently a professor. His research interests include computer arithmetic, VLSI digital filters and VLSI design automation.