Exploring the Processing-in-Memory design space

With the emergence of 3D-DRAM, Processing-in-Memory has once more become of great interest to the research community and industry. Here we present our observations on a subset of the PIM design space. We show how the architectural choices for PIM core frequency and cache sizes will affect the overall power consumption and energy efficiency. We include a detailed power consumption breakdown for an ARM-like core as a PIM core. We show the maximum possible number of PIM cores we can place in the logic layer with respect to a predefined power budget. Additionally, we catalog additional sources of power consumption in a system with PIM such as 3D-DRAM link power and discuss the possible power reduction techniques. We describe the shortcomings of using ARM-like cores for PIM and discuss other alternatives for the PIM cores. Finally, we explore the optimal design choices for the number of cores as a function of performance, utilization, and energy efficiency.     

Implementing a Semantic Service Provision Platform

Seamless integration of information systems plays a key role in the development and maintenance of products. In today’s dynamic market environments, change is the rule rather than the exception. Consequently, the ability to change products is an effective way to adapt to a changing information technology landscape which is an important competitive advantage of a successful company. The vision of service-oriented computing is to capture business relevant functionalities of existing software systems as services and use service composition to form composite applications. Unfortunately, this vision has yet to be achieved. We present here a high-level overview of a semantic service discovery, composition, and enactment system that realizes this vision. Rather than addressing a fully fledged industrial strength system, we present a research prototype that realizes this vision in a narrow application domain to show the general feasibility of automatic semantic discovery, composition and flexible enactment of services. The lessons we learned from implementing this prototype are: a) The requirements regarding the features of logical reasoners for the implementation of “real” scenarios are high. b) A formal and exact specification of the semantics of “real world” services is a laborious task. c) It is hard to find adequate scenarios, because people don’t trust this technology and they don’t like to give the control on business processes to a machine, because questions like “Who is responsible?” arise. Furthermore, the application of automated and flexible service discovery and composition at run-time is only cost-effective if changes and volatilities are frequent in the service landscape.     

The design of a reliable reputation system

Next generation Web 2.0 communities and distributed P2P systems rely on the cooperation of diverse user populations spread across numerous administrative and security domains. Zero accountability via anonymous online identities and divergent interests result in selfish behavior that can disrupt or manipulate networks for personal gain. While “reputation systems” are recognized as a promising means to establish social control for such communities, developing reliable reputation systems remains a challenge. Several unaddressed threats still limit the effectiveness of reputation systems. Furthermore, most existing work on reputations has focused on accurate reputations for stable systems, but not examined the implications of integrating user reputations into scalable distributed infrastructures. The primary goal of this paper is to investigate and address the critical open challenges that limit the effectiveness of reputations. First, we identify a thorough taxonomy on reputation management, and use it as our framework to classify adversarial threats that compromise reliable operation of reputation systems. Second, we survey existing research to address these threats. Finally, we present our solutions to address the two leading reasons for erroneous and misleading values produced by reputation systems today, i.e., user collusion and short-lived online identities. We believe that this paper not only serves as an introduction to reputation systems design, but will also help researchers deploy reliable reputation solutions that contribute towards improving the performance of large distributed applications.     

Is the subjective feel of “presence” an uninteresting goal?

An ideal goal of virtual reality technology is to deliver a complete visual and sensorimotor duplicate of an object: a fully integrated haptic and visual set of stimuli that would make us feel as if we are in the “presence” of the real object in an ordinary situation. The goal is very ambitious, but what is a measure of success? An analysis of presence is much needed, and one of the main tenets of our paper is that an empirical study of the psychological aspects of the feel of presence would constitute the pivotal element of such an analysis; we shall argue that some interesting lessons can be learned about the ideal goal. To sustain our argument, we consider two case studies in turn. The tunnel effect case teaches us that actual stimulation is neither necessary nor sufficient to convey presence. The picture case teaches us that it is possible to learn how to interact to a high degree of success with very impoverished stimuli and successfully compensate for poor stimulation. Research should thus be oriented not towards potentially useless and costly “duplication” of reality, but towards the unexplored potentialities offered by new and complex interfaces.     

An Analysis of Linear Subspace Approaches for Computer Vision and Pattern Recognition

Linear subspace analysis (LSA) has become rather ubiquitous in a wide range of problems arising in pattern recognition and computer vision. The essence of these approaches is that certain structures are intrinsically (or approximately) low dimensional: for example, the factorization approach to the problem of structure from motion (SFM) and principal component analysis (PCA) based approach to face recognition. In LSA, the singular value decomposition (SVD) is usually the basic mathematical tool. However, analysis of the performance, in the presence of noise, has been lacking. We present such an analysis here. First, the “denoising capacity” of the SVD is analysed. Specifically, given a rank-r matrix, corrupted by noise—how much noise remains in the rank-r projected version of that corrupted matrix? Second, we study the “learning capacity” of the LSA-based recognition system in a noise-corrupted environment. Specifically, LSA systems that attempt to capture a data class as belonging to a rank-r column space will be affected by noise in both the training samples (measurement noise will mean the learning samples will not produce the “true subspace”) and the test sample (which will also have measurement noise on top of the ideal clean sample belonging to the “true subspace”). These results should help one to predict aspects of performance and to design more optimal systems in computer vision, particularly in tasks, such as SFM and face recognition. Our analysis agrees with certain observed phenomenon, and these observations, together with our simulations, verify the correctness of our theory.     

Photo annotation: a survey

Due to the large number of photos that are currently being generated, it is very important to have techniques to organize, search for, and retrieve such images. Photo annotation plays a key role in these mechanisms because it can link raw data (photos) to specific information that is essential for human beings to handle large amounts of content. However, the generation of photo annotation is still a difficult problem to solve as part of a well-known challenge called the semantic gap. In this paper, a literature review was conducted with the aim of investigating the most popular methods employed to produce photo annotations. Based on the papers surveyed, we identified that People (“Who?”), Location (“Where?”), and Event (“Where? When?”) are the most important features of photo annotation. We also established comparisons between similar photo annotation methods, highlighting key aspects of the most commonly used approaches. Moreover, we provide an overview of a general photo annotation process and present the main aspects of photo annotation representation comprising formats, context of usage, advantages and disadvantages. Finally, we discuss ways to improve photo annotation methods and present some future research guidelines.     

A NFC-based pervasive solution for city touristic surfing

Context-aware and pervasive computing applications have increased their number during the last decade, thanks to the development of new communication and mobile technologies. These applications cover a wide spectrum of problems, sectors, scenarios, and environments that aim to build smart environments supporting many kinds of human interactions. Tourism is an important economic sector for many cities and countries and therefore a research area where the development of ubiquitous applications is having a great interest. In this paper, we propose a solution oriented to help the user to find the location of interest points within the city and navigate through them. In this work, we propose the use of mobile phones with the near-field communication technology incorporated and Smart Posters disseminated along the city. Indoor and outdoor locations and navigation are allowed, “where is it?”, “what is it?”, “where am I?”, “what is there around me?” and the remaining hits of locations and navigation paradigms are supported by an easy, cheap, and context-awareness system without the need of hard tasks to the user related to system installation or tailoring.     

Scalable visibility color map construction in spatial databases

Recent advances in 3D modeling provide us with real 3D datasets to answer queries, such as “What is the best position for a new billboard?” and “Which hotel room has the best view?” in the presence of obstacles. These applications require measuring and differentiating the visibility of an object (target) from different viewpoints in a dataspace, e.g., a billboard may be seen from many points but is readable only from a few points closer to it. In this paper, we formulate the above problem of quantifying the visibility of (from) a target object from (of) the surrounding area with a visibility color map (VCM). A VCM is essentially defined as a surface color map of the space, where each viewpoint of the space is assigned a color value that denotes the visibility measure of the target from that viewpoint. Measuring the visibility of a target even from a single viewpoint is an expensive operation, as we need to consider factors such as distance, angle, and obstacles between the viewpoint and the target. Hence, a straightforward approach to construct the VCM that requires visibility computation for every viewpoint of the surrounding space of the target is prohibitively expensive in terms of both I/Os and computation, especially for a real dataset comprising thousands of obstacles. We propose an efficient approach to compute the VCM based on a key property of the human vision that eliminates the necessity for computing the visibility for a large number of viewpoints of the space. To further reduce the computational overhead, we propose two approximations; namely, minimum bounding rectangle and tangential approaches with guaranteed error bounds. Our extensive experiments demonstrate the effectiveness and efficiency of our solutions to construct the VCM for real 2D and 3D datasets.     

Physiolytics at the workplace: Affordances and constraints of wearables use from an employee's perspective

Wearables paired with data analytics and machine learning algorithms that measure physiological (and other) parameters are slowly finding their way into our workplace. Several studies have reported positive effects from using such “physiolytics” devices and purported the notion that it may lead to significant workplace safety improvements or to increased awareness among employees concerning unhealthy work practices and other job‐related health and well‐being issues. At the same time, physiolytics may cause an overdependency on technology and create new constraints on privacy, individuality, and personal freedom. While it is easy to understand why organizations are implementing physiolytics, it remains unclear what employees think about using wearables at their workplace. Using an affordance theory lens, we, therefore, explore the mental models of employees who are faced with the introduction of physiolytics as part of corporate wellness or security programs. We identify five distinct user types each of which characterizes a specific viewpoint on physiolytics at the workplace: the freedom loving, the individualist, the cynical, the tech independent, and the balancer. Our findings allow for better understanding the wider implications and possible user responses to the introduction of wearable technologies in occupational settings and address the need for opening up the “user black box” in IS use research.     

Exploring design space for an integrated intelligent system

Understanding the trade-offs available in the design space of intelligent systems is a major unaddressed element in the study of Artificial Intelligence. In this paper, we approach this problem in two ways. First, we discuss the development of our integrated robotic system in terms of its trajectory through design space. Second, we demonstrate the practical implications of architectural design decisions by using this system as an experimental platform for comparing behaviourally similar yet architecturally different systems. The results of this show that our system occupies a “sweet spot” in design space in terms of the cost of moving information between processing components.     

More applicable environmental scanning systems leveraging “modern” information systems

With Ansoff’s article about weak signals as a flagship example, a substantial body of knowledge about environmental scanning systems exists. However, these concepts often go unused in practice. The 2008/2009 economic crisis provided a strong, ongoing impulse for redesigning such information systems (IS). This article develops six guidelines for the conceptual design of environmental scanning systems that are more applicable than those specified by previous research. We start with literature research, which reveals three gaps in existing approaches. Then we develop design guidelines to fill these gaps with the help of “modern” IS. To address the lack of sound requirements analysis, our first design principle proposes 360-degree environmental scanning systems for executives and suggests how to select the most important scanning areas. Three further findings cover weaknesses in the IS model perspective, focusing on more effective implications of weak signals. In terms of method, we propose incorporating scanning results more closely into executives’ decision-making processes. Applying the design guidelines at a raw materials and engineering company, we arrive at a prototype we call the “corporate radar.” It includes an IS-based tree with economic value added at risk on top. The resulting lessons learned help to evaluate our findings and the research method presented here, as well provide concrete starting points for future research.     

Guest Editorial: Reliability Issues in Distributed Systems

TO provide continuity of operations in automated systems, we need to develop techniques that can make them reliable. Many systems such as used in space programs, air traffic control, nuclear plant monitors, ballistic missile defense, etc., demand robust operation. In the past, research efforts have focused on the design and implementation of distributed systems used in such applications. We foresee a need of research effort in the investigation of algorithms and system structures that make error/failure detection, reconfiguration, recovery, and restart of a system feasible with the least amount of interruptions.     

Mona Lisa alive

This paper presents a novel approach for creating self-moving objects using hollow-face illusion. Given a clip of character animation, our approach generates a static object. Looking at the object at different views, a similar deformation can be observed. To accomplish this challenging mission, we give qualitative and quantitative analysis of hollow-face illusion. Methodology in computer vision and human perception are utilized to design the algorithm. A static object is first generated to satisfy the relative motion illusion constraints. The illusion is then strengthened by back projecting the object to the 3D face space. Considering both “bottom-up” visual signal and “top-down” knowledge, the intended illusion can be generated. Experiments have shown the effectiveness of our algorithm. For example, expression varying illusion on an oil painting can be created by our method. The self-moving objects can be used in applications such as design, entertainment, advertisement, and public safety.     

Software agents and agency: A personal information management perspective

This paper considers the concept of agency and the applications of software agents within the field of Personal Information Management (PIM). PIM addresses the complex activities undertaken by individuals when organising their personal information. In the context of Personal Information Management, effective software agents may allow users to obtain information relevant to their tasks, and present it in a form that is directly targeted to the needs of the user.This paper concentrates on the notion of agency and its direct application to PIM tasks. A user-driven approach to the design of agent-based systems is presented. We argue that agent systems will only be successful if both usersand their tasks act as the bases for the design of such systems. An example task domain (searching the World-Wide Web) is introduced and a taxonomy of Web agents for the domain is discussed. Technical issues raised during the preliminary implementation of Web agents are also introduced.     

The effects of recommendations’ presentation on persuasion and satisfaction in a movie recommender system

The explosive growth of Internet applications and content, during the last decade, has revealed an increasing need for information filtering and recommendation. Most research in the area of recommendation systems has focused on designing and implementing efficient algorithms that provide accurate recommendations. However, the selection of appropriate recommendation content and the presentation of information are equally important in creating successful recommender applications. This paper addresses issues related to the presentation of recommendations in the movies domain. The current work reviews previous research approaches and popular recommender systems, and focuses on user persuasion and satisfaction. In our experiments, we compare different presentation methods in terms of recommendations’ organization in a list (i.e. top N-items list and structured overview) and recommendation modality (i.e. simple text, combination of text and image, and combination of text and video). The most efficient presentation methods, regarding user persuasion and satisfaction, proved to be the “structured overview” and the “text and video” interfaces, while a strong positive correlation was also found between user satisfaction and persuasion in all experimental conditions.     

Analytical modeling and mitigation techniques for the energy hole problem in sensor networks

In this paper we investigate the problem of uneven energy consumption in a large class of many-to-one sensor networks. In a many-to-one sensor network, all sensor nodes generate constant bit rate (CBR) data and send them to a single sink via multihop transmissions. This type of sensor network has many potential applications such as environmental monitoring and data gathering. Based on the observation that sensor nodes sitting around the sink need to relay more traffic compared to other nodes in outer sub-regions, our analysis verifies that nodes in inner rings suffer much faster energy consumption rates (ECR) and thus have much shorter expected lifetimes. We term this phenomenon of uneven energy consumption rates as the “energy hole” problem, which may result in severe consequences such as early dysfunction of the entire network. We proposed analytical modeling for this problem, which can help understand the relevance of different factors on energy consumption rates. Using this model, we study the effectiveness of several existing approaches towards mitigating the “energy hole” problem, including deployment assistance, traffic compression and aggregation. We have used simulation results to validate our analysis.     

Defining views in the Binary Relationship Model

The Binary Relationship Model has been praised for the way it not only supports, but practically forces us to model the “deep structures” of the information in the conceptual schema. An adverse effect is that the conceptual schema becomes very large. This, combined with the fact that a Binary Relationship Model schema gives a “flat” representation of the information, makes it very hard to distinguish important concepts of a model from its less important details. Furthermore, the length of DML statements is directly proportional to the size of the schema. What we need for practical applications is a way of keeping the “deep structures” while seeing only the “surface structures”. We need to be able to define views on a conceptual schema. We need to be able to select and derive from the conceptual schema precisely the concepts we are interested in for each application of our model.We propose two new concepts for view definition in the Binary Relationship Model, DOTs and shortcuts. DOTs are dervied object types and shortcuts are derived roles which are used in the definition of derived binary relationship types.     

Rethinking the role of social theory in socio-technical analysis: a critical realist approach to aircraft maintenance

Based on empirical research within the aviation industry we have come to some surprising and sometimes counterintuitive conclusions concerning aircraft maintenance that are relevant for the discussion of social theory and its application towards the explanation and management of socio-technical systems. In this article, the human role in the activity of aircraft maintenance is taken as an example to illustrate the need for critical discussions on social theory in order to better understand safety in socio-technical systems This challenges us to consider the theoretical basis related to how we currently approach the human factor in management of such systems. We propose in the article that Roy Bhaskars' book “The possibility of naturalism—a philosophical critique of the contemporary human sciences (1979)” delivers a compelling social theory from which follows a social ontology of the objects of socio-technical systems that is a necessary precursor to developing applied models and empirical accounts of socio-technical systems.     

Factors influencing flow of object focussed collaboration in collaborative virtual environments

Creativity is believed to be helped by an uncluttered state of mind known as flow and as the trend grows towards less immersive displays to produce an uncluttered workplace, we ask the question “Does immersion matter to the flow of distributed group work?”. The aim of this work is to study the impact of level of immersion on workflow and presence during object focussed distributed group work, and to discuss the relevance of these and other factors to supporting flow and creativity. This is approached through a comprehensive literature survey and significant new results. The study attempts to introduce a breadth of factors and relationships as opposed to proving a hypothesis and thus takes a wide qualitative rather than deep quantitative approach to testing and analysis.