Archives for 2012

Today I read a paper titled “Block-based quantum-logic synthesis”

The abstract is:
In this paper, the problem of constructing an efficient quantum circuit for the implementation of an arbitrary quantum computation is addressed.

To this end, a basic block based on the cosine-sine decomposition method is suggested which contains $l$ qubits.

In addition, a previously proposed quantum-logic synthesis method based on quantum Shannon decomposition is recursively applied to reach unitary gates over $l$ qubits.

Then, the basic block is used and some optimizations are applied to remove redundant gates.

It is shown that the exact value of $l$ affects the number of one-qubit and CNOT gates in the proposed method.

In comparison to the previous synthesis methods, the value of $l$ is examined consequently to improve either the number of CNOT gates or the total number of gates.

The proposed approach is further analyzed by considering the nearest neighbor limitation.

According to our evaluation, the number of CNOT gates is increased by at most a factor of $\frac{5}{3}$ if the nearest neighbor interaction is applied.

Today I read a paper titled “Real-time jam-session support system”

The abstract is:
We propose a method for the problem of real time chord accompaniment of improvised music.

Our implementation can learn an underlying structure of the musical performance and predict next chord.

The system uses Hidden Markov Model to find the most probable chord sequence for the played melody and then a Variable Order Markov Model is used to a) learn the structure (if any) and b) predict next chord.

We implemented our system in Java and MAX/Msp and compared and evaluated using objective (prediction accuracy) and subjective (questionnaire) evaluation methods.

Today I read a paper titled “Tales of 34 iPhone Users: How they change and why they are different”

The abstract is:
We present results from a longitudinal study of 34 iPh-one 3GS users, called LiveLab.

LiveLab collected unprecedented usage data through an in-device, programmable logger and several structured interviews with the participants throughout the study.

We have four objectives in writing this paper: (i) share the findings with the research community; (ii) provide insights guiding the design of smartphone systems and applications; (iii) demonstrate the power of prudently designed longitudinal field studies and the power of advanced research methods; and (iv) raise important questions that the research community can help answer in a collaborative, multidisciplinary manner.

We show how the smartphone usage changes over the year and why the users are different (and similar) in their usage.

In particular, our findings highlight application and web usage dynamics, the influence of socioeconomic status (SES) on usage, and the shortcomings of iPhone 3GS and its ecosystem.

We further show that distinct classes of usage patterns exist, and these classes are best served by different phone designs, instead of the one-size-fits-all phone Apple provides.

Our findings are significant not only for understanding smartphone users but also in guiding device and application development and optimizations.

While we present novel results that can only be produced by a study of this nature, we also raise new research questions to be investigated by the mobile research community.

Today I read a paper titled “Hubs and Clusters in the Evolving U. S. Internal Migration Network”

The abstract is:
Most nations of the world periodically publish N x N origin-destination tables, recording the number of people who lived in geographic subdivision i at time t and j at t+1.

We have developed and widely applied to such national tables and other analogous (weighted, directed) socioeconomic networks, a two-stage–double-standardization and (strong component) hierarchical clustering–procedure.

Previous applications of this methodology and related analytical issues are discussed.

Its use is illustrated in a large-scale study, employing recorded United States internal migration flows between the 3,000+ county-level units of the nation for the periods 1965-1970 and 1995-2000.

Prominent, important features–such as ”cosmopolitan hubs” and “functional regions”–are extracted from master dendrograms.

The extent to which such characteristics have varied over the intervening thirty years is evaluated.

Today I read a paper titled “Discrete stochastic processes, replicator and Fokker-Planck equations of coevolutionary dynamics in finite and infinite populations”

The abstract is:
Finite-size fluctuations in coevolutionary dynamics arise in models of biological as well as of social and economic systems.

This brief tutorial review surveys a systematic approach starting from a stochastic process discrete both in time and state.

The limit $N\to \infty$ of an infinite population can be considered explicitly, generally leading to a replicator-type equation in zero order, and to a Fokker-Planck-type equation in first order in $1/\sqrt{N}$.

Consequences and relations to some previous approaches are outlined.

Today I read a paper titled “Specular holography”

The abstract is:
By tooling an spot-illuminated surface to control the flow of specular glints under motion, one can produce holographic view-dependent imagery.

This paper presents the differential equation that governs the shape of the specular surfaces, and illustrates how solutions can be constructed for different kinds of motion, lighting, host surface geometries, and fabrication constraints, leading to some novel forms of holography.

Today I read a paper titled “Wikipedia information flow analysis reveals the scale-free architecture of the Semantic Space”

The abstract is:
In this paper we extract the topology of the semantic space in its encyclopedic acception, measuring the semantic flow between the different entries of the largest modern encyclopedia, Wikipedia, and thus creating a directed complex network of semantic flows.

Notably at the percolation threshold the semantic space is characterised by scale-free behaviour at different levels of complexity and this relates the semantic space to a wide range of biological, social and linguistics phenomena.

In particular we find that the cluster size distribution, representing the size of different semantic areas, is scale-free.

Moreover the topology of the resulting semantic space is scale-free in the connectivity distribution and displays small-world properties.

However its statistical properties do not allow a classical interpretation via a generative model based on a simple multiplicative process.

After giving a detailed description and interpretation of the topological properties of the semantic space, we introduce a stochastic model of content-based network, based on a copy and mutation algorithm and on the Heaps’ law, that is able to capture the main statistical properties of the analysed semantic space, including the Zipf’s law for the word frequency distribution.

Today I read a paper titled “Modeling the Experience of Emotion”

The abstract is:
Affective computing has proven to be a viable field of research comprised of a large number of multidisciplinary researchers resulting in work that is widely published.

The majority of this work consists of computational models of emotion recognition, computational modeling of causal factors of emotion and emotion expression through rendered and robotic faces.

A smaller part is concerned with modeling the effects of emotion, formal modeling of cognitive appraisal theory and models of emergent emotions.

Part of the motivation for affective computing as a field is to better understand emotional processes through computational modeling.

One of the four major topics in affective computing is computers that have emotions (the others are recognizing, expressing and understanding emotions).

A critical and neglected aspect of having emotions is the experience of emotion (Barrett, Mesquita, Ochsner, and Gross, 2007): what does the content of an emotional episode look like, how does this content change over time and when do we call the episode emotional.

Few modeling efforts have these topics as primary focus.

The launch of a journal on synthetic emotions should motivate research initiatives in this direction, and this research should have a measurable impact on emotion research in psychology.

I show that a good way to do so is to investigate the psychological core of what an emotion is: an experience.

I present ideas on how the experience of emotion could be modeled and provide evidence that several computational models of emotion are already addressing the issue.

Today I read a paper titled “Naturally Supervised Learning in Manipulable Technologies”

The abstract is:
The relationship between physiological systems and modern electromechanical technologies is fast becoming intimate with high degrees of complex interaction.

It can be argued that muscular function, limb movements, and touch perception serve supervisory functions for movement control in motion and touch-based (e.g.

manipulable) devices/interfaces and human-machine interfaces in general.

To get at this hypothesis requires the use of novel techniques and analyses which demonstrate the multifaceted and regulatory role of adaptive physiological processes in these interactions.

Neuromechanics is an approach that unifies the role of physiological function, motor performance, and environmental effects in determining human performance.

A neuromechanical perspective will be used to explain the effect of environmental fluctuations on supervisory mechanisms, which leads to adaptive physiological responses.

Three experiments are presented using two different types of virtual environment that allowed for selective switching between two sets of environmental forces.

This switching was done in various ways to maximize the variety of results.

Electromyography (EMG) and kinematic information contributed to the development of human performance-related measures.

Both descriptive and specialized analyses were conducted: peak amplitude analysis, loop trace analysis, and the analysis of unmatched muscle power.

Results presented here provide a window into performance under a range of conditions.

These analyses also demonstrated myriad consequences for force-related fluctuations on dynamic physiological regulation.

The findings presented here could be applied to the dynamic control of touch-based and movement-sensitive human-machine systems.

In particular, the design of systems such as human-robotic systems, touch screen devices, and rehabilitative technologies could benefit from this research.

Today I read a paper titled “Volume-Enclosing Surface Extraction”

The abstract is:
In this paper we present a new method, which allows for the construction of triangular isosurfaces from three-dimensional data sets, such as 3D image data and/or numerical simulation data that are based on regularly shaped, cubic lattices.

This novel volume-enclosing surface extraction technique, which has been named VESTA, can produce up to six different results due to the nature of the discretized 3D space under consideration.

VESTA is neither template-based nor it is necessarily required to operate on 2x2x2 voxel cell neighborhoods only.

The surface tiles are determined with a very fast and robust construction technique while potential ambiguities are detected and resolved.

Here, we provide an in-depth comparison between VESTA and various versions of the well-known and very popular Marching Cubes algorithm for the very first time.

In an application section, we demonstrate the extraction of VESTA isosurfaces for various data sets ranging from computer tomographic scan data to simulation data of relativistic hydrodynamic fireball expansions.

Today I read a paper titled “Robust Motion Control for Mobile Manipulator Using Resolved Acceleration and Proportional-Integral Active Force Control”

The abstract is:
A resolved acceleration control (RAC) and proportional-integral active force control (PIAFC) is proposed as an approach for the robust motion control of a mobile manipulator (MM) comprising a differentially driven wheeled mobile platform with a two-link planar arm mounted on top of the platform.

The study emphasizes on the integrated kinematic and dynamic control strategy in which the RAC is used to manipulate the kinematic component while the PIAFC is implemented to compensate the dynamic effects including the bounded known/unknown disturbances and uncertainties.

The effectivenss and robustness of the proposed scheme are investigated through a rigorous simulation study and later complemented with experimental results obtained through a number of experiments performed on a fully developed working prototype in a laboratory environment.

A number of disturbances in the form of vibratory and impact forces are deliberately introduced into the system to evaluate the system performances.

The investigation clearly demonstrates the extreme robustness feature of the proposed control scheme compared to other systems considered in the study.

Today I read a paper titled “Peer-to-Peer Multimedia Sharing based on Social Norms”

The abstract is:
Empirical data shows that in the absence of incentives, a peer participating in a Peer-to-Peer (P2P) network wishes to free-riding.

Most solutions for providing incentives in P2P networks are based on direct reciprocity, which are not appropriate for most P2P multimedia sharing networks due to the unique features exhibited by such networks: large populations of anonymous agents interacting infrequently, asymmetric interests of peers, network errors, and multiple concurrent transactions.

In this paper, we design and rigorously analyze a new family of incentive protocols that utilizes indirect reciprocity which is based on the design of efficient social norms.

In the proposed P2P protocols, the social norms consist of a social strategy, which represents the rule prescribing to the peers when they should or should not provide content to other peers, and a reputation scheme, which rewards or punishes peers depending on whether they comply or not with the social strategy.

We first define the concept of a sustainable social norm, under which no peer has an incentive to deviate.

We then formulate the problem of designing optimal social norms, which selects the social norm that maximizes the network performance among all sustainable social norms.

Hence, we prove that it becomes in the self-interest of peers to contribute their content to the network rather than to free-ride.

We also investigate the impact of various punishment schemes on the social welfare as well as how should the optimal social norms be designed if altruistic and malicious peers are active in the network.

Our results show that optimal social norms are capable of providing significant improvements in the sharing efficiency of multimedia P2P networks.

Today I read a paper titled “The Fast Haar Wavelet Transform for Signal & Image Processing”

The abstract is:
A method for the design of Fast Haar wavelet for signal processing and image processing has been proposed.

In the proposed work, the analysis bank and synthesis bank of Haar wavelet is modified by using polyphase structure.

Finally, the Fast Haar wavelet was designed and it satisfies alias free and perfect reconstruction condition.

Computational time and computational complexity is reduced in Fast Haar wavelet transform.

Today I read a paper titled “Fish recognition based on the combination between robust feature selection, image segmentation and geometrical parameter techniques using Artificial Neural Network and Decision Tree”

The abstract is:
We presents in this paper a novel fish classification methodology based on a combination between robust feature selection, image segmentation and geometrical parameter techniques using Artificial Neural Network and Decision Tree.

Unlike existing works for fish classification, which propose descriptors and do not analyze their individual impacts in the whole classification task and do not make the combination between the feature selection, image segmentation and geometrical parameter, we propose a general set of features extraction using robust feature selection, image segmentation and geometrical parameter and their correspondent weights that should be used as a priori information by the classifier.

In this sense, instead of studying techniques for improving the classifiers structure itself, we consider it as a black box and focus our research in the determination of which input information must bring a robust fish discrimination.The main contribution of this paper is enhancement recognize and classify fishes based on digital image and To develop and implement a novel fish recognition prototype using global feature extraction, image segmentation and geometrical parameters, it have the ability to Categorize the given fish into its cluster and Categorize the clustered fish into poison or non-poison fish, and categorizes the non-poison fish into its family .

Today I read a paper titled “Beyond the Drawing Board: Toward More Effective Use of Whiteboard Content”

The abstract is:
We developed a system that augments traditional office whiteboards with computation for the purposes of retrieving, reusing, and sharing whiteboard content.

Our system automatically captures changes to whiteboard images, detects significant changes, and identifies potential collaborative activities.

Users then browse and search the collection of images captured from their camera or shared from other users’ cameras based on aspects such as location, time, collaboration, etc.

We report on the results of a formative study and on an evaluation of effectiveness of our system, and discuss additional functionality that can be built on our framework.

Today I read a paper titled “A two-stage algorithm for extracting the multiscale backbone of complex weighted networks”

The abstract is:
The central problem of concern to Serrano, Boguna and Vespignani (“Extracting the multiscale backbone of complex weighted networks”, Proc Natl Acad Sci 106:6483-6488 [2009]) can be effectively and elegantly addressed using a well-established two-stage algorithm that has been applied to internal migration flows for numerous nations and several other forms of “transaction flow data”.

Today I read a paper titled “The Ethics of Robotics”

The abstract is:
The three laws of Robotics first appeared together in Isaac Asimov’s story ‘Runaround’ after being mentioned in some form or the other in previous works by Asimov.

These three laws commonly known as the three laws of robotics are the earliest forms of depiction for the needs of ethics in Robotics.

In simplistic language Isaac Asimov is able to explain what rules a robot must confine itself to in order to maintain societal sanctity.

However, even though they are outdated they still represent some of our innate fears which are beginning to resurface in present day 21st Century.

Our society is on the advent of a new revolution; a revolution led by advances in Computer Science, Artificial Intelligence & Nanotechnology.

Some of our advances have been so phenomenal that we surpassed what was predicted by the Moore’s law.

With these advancements comes the fear that our future may be at the mercy of these androids.

Humans today are scared that we, ourselves, might create something which we cannot control.

We may end up creating something which can not only learn much faster than anyone of us can, but also evolve faster than what the theory of evolution has allowed us to.

The greatest fear is not only that we might lose our jobs to these intelligent beings, but that these beings might end up replacing us at the top of the cycle.

The public hysteria has been heightened more so by a number of cultural works which depict annihilation of the human race by robots.

Right from Frankenstein to I, Robot mass media has also depicted such issues.

This paper is an effort to understand the need for ethics in Robotics or simply termed as Roboethics.

This is achieved by the study of artificial beings and the thought being put behind them.

By the end of the paper, however, it is concluded that there isn’t a need for ethical robots but more so ever a need for ethical roboticists.

Today I read a paper titled “The Role of Head-Up Display in Computer- Assisted Instruction”

The abstract is:
We investigated the role of HUDs in CAI.

HUDs have been used in various situations in daily lives by recent downsizing and cost down of the display devices.

CAI is one of the promising applications for HUDs.

We have developed an HUD-based CAI system for effectively presenting instructions of the equipment in the transportable earth station.

This chapter described HUDs in CAI from a viewpoint of human-computer interaction based on the development experience.

Today I read a paper titled “Profile Based Sub-Image Search in Image Databases”

The abstract is:
Sub-image search with high accuracy in natural images still remains a challenging problem.

This paper proposes a new feature vector called profile for a keypoint in a bag of visual words model of an image.

The profile of a keypoint captures the spatial geometry of all the other keypoints in an image with respect to itself, and is very effective in discriminating true matches from false matches.

Sub-image search using profiles is a single-phase process requiring no geometric validation, yields high precision on natural images, and works well on small visual codebook.

The proposed search technique differs from traditional methods that first generate a set of candidates disregarding spatial information and then verify them geometrically.

Conventional methods also use large codebooks.

We achieve a precision of 81% on a combined data set of synthetic and real natural images using a codebook size of 500 for top-10 queries; that is 31% higher than the conventional candidate generation approach.

Today I read a paper titled “Robustness of interdependent networks under targeted attack”

The abstract is:
When an initial failure of nodes occurs in interdependent networks, a cascade of failure between the networks occurs.

Earlier studies focused on random initial failures.

Here we study the robustness of interdependent networks under targeted attack on high or low degree nodes.

We introduce a general technique and show that the {\it targeted-attack} problem in interdependent networks can be mapped to the {\it random-attack} problem in a transformed pair of interdependent networks.

We find that when the highly connected nodes are protected and have lower probability to fail, in contrast to single scale free (SF) networks where the percolation threshold $p_c=0$, coupled SF networks are significantly more vulnerable with $p_c$ significantly larger than zero.

The result implies that interdependent networks are difficult to defend by strategies such as protecting the high degree nodes that have been found useful to significantly improve robustness of single networks.

Today I read a paper titled “Evolutionary Games defined at the Network Mesoscale: The Public Goods game”

The abstract is:
The evolutionary dynamics of the Public Goods game addresses the emergence of cooperation within groups of individuals.

However, the Public Goods game on large populations of interconnected individuals has been usually modeled without any knowledge about their group structure.

In this paper, by focusing on collaboration networks, we show that it is possible to include the mesoscopic information about the structure of the real groups by means of a bipartite graph.

We compare the results with the projected (coauthor) and the original bipartite graphs and show that cooperation is enhanced by the mesoscopic structure contained.

We conclude by analyzing the influence of the size of the groups in the evolutionary success of cooperation.