OpenRaiser/Intern-Atlas huggingface dataset:
Managing Critical Spreadsheets in a Compliant Environment
Venue: arXiv cs.SE 2008
Year: 2008

The use of uncontrolled financial spreadsheets can expose organizations to unacceptable business and compliance risks, including errors in the financial reporting process, spreadsheet misuse and fraud, or even significant operational errors. These risks have been well documented and thoroughly researched. With the advent of regulatory mandates such as SOX 404 and FDICIA in the U.S., and MiFID, Basel II and Combined Code in the UK and Europe, leading tax and audit firms are now recommending that organizations automate their internal controls over critical spreadsheets and other end-user computing applications, including Microsoft Access databases. At a minimum, auditors mandate version control, change control and access control for operational spreadsheets, with more advanced controls for critical financial spreadsheets. This paper summarises the key issues regarding the establishment and maintenance of control of Business Critical spreadsheets.
A Structured Methodology for Spreadsheet Modelling
Venue: arXiv cs.SE 2008
Year: 2008

In this paper, we discuss the problem of the software engineering of a class of business spreadsheet models. A methodology for structured software development is proposed, which is based on structured analysis of data, represented as Jackson diagrams. It is shown that this analysis allows a straightforward modularisation, and that individual modules may be represented with indentation in the block-structured form of structured programs. The benefits of structured format are discussed, in terms of comprehensibility, ease of maintenance, and reduction in errors. The capability of the methodology to provide a modular overview in the model is described, and examples are given. The potential for a reverse-engineering tool, to transform existing spreadsheet models is discussed.
Risk Assessment For Spreadsheet Developments: Choosing Which Models to Audit
Venue: arXiv cs.SE 2008
Year: 2008

Errors in spreadsheet applications and models are alarmingly common (some authorities, with justification cite spreadsheets containing errors as the norm rather than the exception). Faced with this body of evidence, the auditor can be faced with a huge task - the temptation may be to launch code inspections for every spreadsheet in an organisation. This can be very expensive and time-consuming. This paper describes risk assessment based on the "SpACE" audit methodology used by H M Customs & Excise's tax inspectors. This allows the auditor to target resources on the spreadsheets posing the highest risk of error, and justify the deployment of those resources to managers and clients. Since the opposite of audit risk is audit assurance the paper also offers an overview of some elements of good practice in the use of spreadsheets in business.
From Data Topology to a Modular Classifier
Venue: arXiv cs.LG 2008
Year: 2008

This article describes an approach to designing a distributed and modular neural classifier. This approach introduces a new hierarchical clustering that enables one to determine reliable regions in the representation space by exploiting supervised information. A multilayer perceptron is then associated with each of these detected clusters and charged with recognizing elements of the associated cluster while rejecting all others. The obtained global classifier is comprised of a set of cooperating neural networks and completed by a K-nearest neighbor classifier charged with treating elements rejected by all the neural networks. Experimental results for the handwritten digit recognition problem and comparison with neural and statistical nonmodular classifiers are given.
Network Connection Games with Disconnected Equilibria
Venue: arXiv cs.GT 2008
Year: 2008

In this paper we extend a popular non-cooperative network creation game (NCG) to allow for disconnected equilibrium networks. There are n players, each is a vertex in a graph, and a strategy is a subset of players to build edges to. For each edge a player must pay a cost α, and the individual cost for a player represents a trade-off between edge costs and shortest path lengths to all other players. We extend the model to a penalized game (PCG), for which we reduce the penalty counted towards the individual cost for a pair of disconnected players to a finite value β. Our analysis concentrates on existence, structure, and cost of disconnected Nash and strong equilibria. Although the PCG is not a potential game, pure Nash equilibria always and pure strong equilibria very often exist. We provide tight conditions under which disconnected Nash (strong) equilibria can evolve. Components of these equilibria must be Nash (strong) equilibria of a smaller NCG. However, in contrast to the NCG, for almost all parameter values no tree is a stable component. Finally, we present a detailed characterization of the price of anarchy that reveals cases in which the price of anarchy is Θ(n) and thus several orders of magnitude larger than in the NCG. Perhaps surprisingly, the strong price of anarchy increases to at most 4. This indicates that global communication and coordination can be extremely valuable to overcome socially inferior topologies in distributed selfish network design.
Quantization of Prior Probabilities for Hypothesis Testing
Venue: arXiv cs.IT 2008
Year: 2008

Bayesian hypothesis testing is investigated when the prior probabilities of the hypotheses, taken as a random vector, are quantized. Nearest neighbor and centroid conditions are derived using mean Bayes risk error as a distortion measure for quantization. A high-resolution approximation to the distortion-rate function is also obtained. Human decision making in segregated populations is studied assuming Bayesian hypothesis testing with quantized priors.
Channels that Heat Up
Venue: arXiv cs.IT 2008
Year: 2008

This work considers an additive noise channel where the time-k noise variance is a weighted sum of the channel input powers prior to time k. This channel is motivated by point-to-point communication between two terminals that are embedded in the same chip. Transmission heats up the entire chip and hence increases the thermal noise at the receiver. The capacity of this channel (both with and without feedback) is studied at low transmit powers and at high transmit powers. At low transmit powers, the slope of the capacity-vs-power curve at zero is computed and it is shown that the heating-up effect is beneficial. At high transmit powers, conditions are determined under which the capacity is bounded, i.e., under which the capacity does not grow to infinity as the allowed average power tends to infinity.
On Secure Distributed Implementations of Dynamic Access Control
Venue: arXiv cs.CR 2008
Year: 2008

Distributed implementations of access control abound in distributed storage protocols. While such implementations are often accompanied by informal justifications of their correctness, our formal analysis reveals that their correctness can be tricky. In particular, we discover several subtleties in a standard protocol based on capabilities, that can break security under a simple specification of access control. At the same time, we show a sensible refinement of the specification for which a secure implementation of access control is possible. Our models and proofs are formalized in the applied pi calculus, following some new techniques that may be of independent interest. Finally, we indicate how our principles can be applied to securely distribute other state machines.
On the Design of Universal LDPC Codes
Venue: arXiv cs.IT 2008
Year: 2008

Low-density parity-check (LDPC) coding for a multitude of equal-capacity channels is studied. First, based on numerous observations, a conjecture is stated that when the belief propagation decoder converges on a set of equal-capacity channels, it would also converge on any convex combination of those channels. Then, it is proved that when the stability condition is satisfied for a number of channels, it is also satisfied for any channel in their convex hull. For the purpose of code design, a method is proposed which can decompose every symmetric channel with capacity C into a set of identical-capacity basis channels. We expect codes that work on the basis channels to be suitable for any channel with capacity C. Such codes are found and in comparison with existing LDPC codes that are designed for specific channels, our codes obtain considerable coding gains when used across a multitude of channels.
Succinct Greedy Graph Drawing in the Hyperbolic Plane
Venue: arXiv cs.CG 2008
Year: 2008

We describe an efficient method for drawing any n-vertex simple graph G in the hyperbolic plane. Our algorithm produces greedy drawings, which support greedy geometric routing, so that a message M between any pair of vertices may be routed geometrically, simply by having each vertex that receives M pass it along to any neighbor that is closer in the hyperbolic metric to the message's eventual destination. More importantly, for networking applications, our algorithm produces succinct drawings, in that each of the vertex positions in one of our embeddings can be represented using O(log n) bits and the calculation of which neighbor to send a message to may be performed efficiently using these representations. These properties are useful, for example, for routing in sensor networks, where storage and bandwidth are limited.
Cluster Development and Knowledge Exchange in Supply Chain
Venue: arXiv cs.CY 2008
Year: 2008

Industry cluster and supply chain are in focus of every countries which rely on knowledge-based economy. Both focus on improving the competitiveness of firm in the industry in the different aspect. This paper tries to illustrate how the industry cluster can increase the supply chain performance. Then, the proposed methodology concentrates on the collaboration and knowledge exchange in supply chain. For improving the capability of the proposed methodology, information technology is applied to facilitate the communication and the exchange of knowledge between the actors of the supply chain within the cluster. The supply chain of French stool producer was used as a case study to validate the methodology and to demonstrate the result of the study.
An Ontology-based Knowledge Management System for Industry Clusters
Venue: arXiv cs.AI 2008
Year: 2008

Knowledge-based economy forces companies in the nation to group together as a cluster in order to maintain their competitiveness in the world market. The cluster development relies on two key success factors which are knowledge sharing and collaboration between the actors in the cluster. Thus, our study tries to propose knowledge management system to support knowledge management activities within the cluster. To achieve the objectives of this study, ontology takes a very important role in knowledge management process in various ways; such as building reusable and faster knowledge-bases, better way for representing the knowledge explicitly. However, creating and representing ontology create difficulties to organization due to the ambiguity and unstructured of source of knowledge. Therefore, the objectives of this paper are to propose the methodology to create and represent ontology for the organization development by using knowledge engineering approach. The handicraft cluster in Thailand is used as a case study to illustrate our proposed methodology.
On Peak versus Average Interference Power Constraints for Protecting Primary Users in Cognitive Radio Networks
Venue: arXiv cs.IT 2008
Year: 2008

This paper considers spectrum sharing for wireless communication between a cognitive radio (CR) link and a primary radio (PR) link. It is assumed that the CR protects the PR transmission by applying the so-called interference-temperature constraint, whereby the CR is allowed to transmit regardless of the PR's on/off status provided that the resultant interference power level at the PR receiver is kept below some predefined threshold. For the fading PR and CR channels, the interference-power constraint at the PR receiver is usually one of the following two types: One is to regulate the average interference power (AIP) over all the fading states, while the other is to limit the peak interference power (PIP) at each fading state. From the CR's perspective, given the same average and peak power threshold, the AIP constraint is more favorable than the PIP counterpart because of its more flexibility for dynamically allocating transmit powers over the fading states. On the contrary, from the perspective of protecting the PR, the more restrictive PIP constraint appears at a first glance to be a better option than the AIP. Some surprisingly, this paper shows that in terms of various forms of capacity limits achievable for the PR fading channel, e.g., the ergodic and outage capacities, the AIP constraint is also superior over the PIP. This result is based upon an interesting interference diversity phenomenon, i.e., randomized interference powers over the fading states in the AIP case are more advantageous over deterministic ones in the PIP case for minimizing the resultant PR capacity losses. Therefore, the AIP constraint results in larger fading channel capacities than the PIP for both the CR and PR transmissions.
Onboard Multivariable Controller Design for a Small Scale Helicopter Using Coefficient Diagram Method
Venue: arXiv cs.RO 2008
Year: 2008

A mini scale helicopter exhibits not only increased sensitivity to control inputs and disturbances, but also higher bandwidth of its dynamics. These properties make model helicopters, as a flying robot, more difficult to control. The dynamics model accuracy will determine the performance of the designed controller. It is attractive in this regards to have a controller that can accommodate the unmodeled dynamics or parameter changes and perform well in such situations. Coefficient Diagram Method (CDM) is chosen as the candidate to synthesize such a controller due to its simplicity and convenience in demonstrating integrated performance measures including equivalent time constant, stability indices and robustness. In this study, CDM is implemented for a design of multivariable controller for a small scale helicopter during hover and cruise flight. In the synthesis of MIMO CDM, good design common sense based on hands-on experience is necessary. The low level controller algorithm is designed as part of hybrid supervisory control architecture to be implemented on an onboard computer system. Its feasibility and performance are evaluated based on its robustness, desired time domain system responses and compliance to hard-real time requirements.
The Euler-Poincare theory of Metamorphosis
Venue: arXiv cs.CV 2008
Year: 2008

In the pattern matching approach to imaging science, the process of ``metamorphosis'' is template matching with dynamical templates. Here, we recast the metamorphosis equations of into the Euler-Poincare variational framework of and show that the metamorphosis equations contain the equations for a perfect complex fluid \cite{Ho2002}. This result connects the ideas underlying the process of metamorphosis in image matching to the physical concept of order parameter in the theory of complex fluids. After developing the general theory, we reinterpret various examples, including point set, image and density metamorphosis. We finally discuss the issue of matching measures with metamorphosis, for which we provide existence theorems for the initial and boundary value problems.
Towards sustainable transport: wireless detection of passenger trips on public transport buses
Venue: arXiv cs.CY 2008
Year: 2008

An important problem in creating efficient public transport is obtaining data about the set of trips that passengers make, usually referred to as an Origin/Destination (OD) matrix. Obtaining this data is problematic and expensive in general, especially in the case of buses because on-board ticketing systems do not record where and when passengers get off a bus. In this paper we describe a novel and inexpensive system that uses off-the-shelf Bluetooth hardware to accurately record passenger journeys. Here we show how our system can be used to derive passenger OD matrices, and additionally we show how our data can be used to further improve public transport services.
3-connected Planar Graph Isomorphism is in Log-space
Venue: arXiv cs.CC 2008
Year: 2008

We show that the isomorphism of 3-connected planar graphs can be decided in deterministic log-space. This improves the previously known bound UL$\cap$coUL of Thierauf and Wagner.
Capacity of Block-Memoryless Channels with Causal Channel Side Information
Venue: arXiv cs.IT 2008
Year: 2008

The capacity of a time-varying block-memoryless channel in which the transmitter and the receiver have access to (possibly different) noisy causal channel side information (CSI) is obtained. It is shown that the capacity formula obtained in this correspondence reduces to the capacity formula reported in \cite{Gold07} for the special case where the transmitter CSI is a deterministic function of the receiver CSI.
Fair and Efficient TCP Access in the IEEE 802.11 Infrastructure Basic Service Set
Venue: arXiv cs.NI 2008
Year: 2008

When the stations in an IEEE 802.11 infrastructure Basic Service Set (BSS) employ Transmission Control Protocol (TCP) in the transport layer, this exacerbates per-flow unfair access which is a direct result of uplink/downlink bandwidth asymmetry in the BSS. We propose a novel and simple analytical model to approximately calculate the per-flow TCP congestion window limit that provides fair and efficient TCP access in a heterogeneous wired-wireless scenario. The proposed analysis is unique in that it considers the effects of varying number of uplink and downlink TCP flows, differing Round Trip Times (RTTs) among TCP connections, and the use of delayed TCP Acknowledgment (ACK) mechanism. Motivated by the findings of this analysis, we design a link layer access control block to be employed only at the Access Point (AP) in order to resolve the unfair access problem. The novel and simple idea of the proposed link layer access control block is employing a congestion control and filtering algorithm on TCP ACK packets of uplink flows, thereby prioritizing the access of TCP data packets of downlink flows at the AP. Via simulations, we show that short- and long-term fair access can be provisioned with the introduction of the proposed link layer access control block to the protocol stack of the AP while improving channel utilization and access delay.
Utilisation des grammaires probabilistes dans les tâches de segmentation et d'annotation prosodique
Venue: arXiv cs.LG 2008
Year: 2008

Nous présentons dans cette contribution une approche à la fois symbolique et probabiliste permettant d'extraire l'information sur la segmentation du signal de parole à partir d'information prosodique. Nous utilisons pour ce faire des grammaires probabilistes possédant une structure hiérarchique minimale. La phase de construction des grammaires ainsi que leur pouvoir de prédiction sont évalués qualitativement ainsi que quantitativement. ----- Methodologically oriented, the present work sketches an approach for prosodic information retrieval and speech segmentation, based on both symbolic and probabilistic information. We have recourse to probabilistic grammars, within which we implement a minimal hierarchical structure. Both the stages of probabilistic grammar building and its testing in prediction are explored and quantitatively and qualitatively evaluated.
Scheduling Sensors by Tiling Lattices
Venue: arXiv cs.NI 2008
Year: 2008

Suppose that wirelessly communicating sensors are placed in a regular fashion on the points of a lattice. Common communication protocols allow the sensors to broadcast messages at arbitrary times, which can lead to problems should two sensors broadcast at the same time. It is shown that one can exploit a tiling of the lattice to derive a deterministic periodic schedule for the broadcast communication of sensors that is guaranteed to be collision-free. The proposed schedule is shown to be optimal in the number of time slots.
The end of Sleeping Beauty's nightmare
Venue: arXiv cs.AI 2008
Year: 2008

The way a rational agent changes her belief in certain propositions/hypotheses in the light of new evidence lies at the heart of Bayesian inference. The basic natural assumption, as summarized in van Fraassen's Reflection Principle ([1984]), would be that in the absence of new evidence the belief should not change. Yet, there are examples that are claimed to violate this assumption. The apparent paradox presented by such examples, if not settled, would demonstrate the inconsistency and/or incompleteness of the Bayesian approach and without eliminating this inconsistency, the approach cannot be regarded as scientific. The Sleeping Beauty Problem is just such an example. The existing attempts to solve the problem fall into three categories. The first two share the view that new evidence is absent, but differ about the conclusion of whether Sleeping Beauty should change her belief or not, and why. The third category is characterized by the view that, after all, new evidence (although hidden from the initial view) is involved. My solution is radically different and does not fall in either of these categories. I deflate the paradox by arguing that the two different degrees of belief presented in the Sleeping Beauty Problem are in fact beliefs in two different propositions, i.e. there is no need to explain the (un)change of belief.
Dynamic Network of Concepts from Web-Publications
Venue: arXiv cs.IT 2008
Year: 2008

The network, the nodes of which are concepts (people's names, companies' names, etc.), extracted from web-publications, is considered. A working algorithm of extracting such concepts is presented. Edges of the network under consideration refer to the reference frequency which depends on the fact how many times the concepts, which correspond to the nodes, are mentioned in the same documents. Web-documents being published within a period of time together form an information flow, which defines the dynamics of the network studied. The phenomenon of its structure stability, when the number of web-publications, constituting its formation bases, increases, is discussed
Competitive Design of Multiuser MIMO Systems based on Game Theory: A Unified View
Venue: arXiv cs.IT 2008
Year: 2008

This paper considers the noncooperative maximization of mutual information in the Gaussian interference channel in a fully distributed fashion via game theory. This problem has been studied in a number of papers during the past decade for the case of frequency-selective channels. A variety of conditions guaranteeing the uniqueness of the Nash Equilibrium (NE) and convergence of many different distributed algorithms have been derived. In this paper we provide a unified view of the state-of-the-art results, showing that most of the techniques proposed in the literature to study the game, even though apparently different, can be unified using our recent interpretation of the waterfilling operator as a projection onto a proper polyhedral set. Based on this interpretation, we then provide a mathematical framework, useful to derive a unified set of sufficient conditions guaranteeing the uniqueness of the NE and the global convergence of waterfilling based asynchronous distributed algorithms. The proposed mathematical framework is also instrumental to study the extension of the game to the more general MIMO case, for which only few results are available in the current literature. The resulting algorithm is, similarly to the frequency-selective case, an iterative asynchronous MIMO waterfilling algorithm. The proof of convergence hinges again on the interpretation of the MIMO waterfilling as a matrix projection, which is the natural generalization of our results obtained for the waterfilling mapping in the frequency-selective case.