Search

The individual consistency and the consensus degree are two basic measures to conduct group decision making with reciprocal preference relations. The existing frameworks to manage individual consistency and consensus degree have been investigated intensively and follow a common resolution scheme composed by the two phases: the consistency improving process, and the consensus reaching process. But in these frameworks, the individual consistency will often be destroyed in the consensus reaching process, leading to repeat the consistency improving process, which is time consuming. In order to avoid repeating the consistency improving process, a consensus reaching process with individual consistency control is proposed in this paper. This novel consensus approach is based on the design of an optimization-based consensus rule, which can be used to determine the adjustment range of each preference value guaranteeing the individual consistency across the process. Finally, theoretical and numerical analysis are both used to justify the validity of our proposal. [ABSTRACT FROM AUTHOR]

Suppose that we are given a time series where consecutive samples are believed to come from a probabilistic source, that the source changes from time to time and that the total number of sources is fixed. Our objective is to estimate the distributions of the sources. A standard approach to this problem is to model the data as a hidden Markov model (HMM). However, since the data often lacks the Markov or the stationarity properties of an HMM, one can ask whether this approach is still suitable or perhaps another approach is required. In this paper, we show that a maximum likelihood HMM estimator can be used to approximate the source distributions in a much larger class of models than HMMs. Specifically, we propose a natural and fairly general non-stationary model of the data, where the only restriction is that the sources do not change too often. Our main result shows that for this model, a maximum-likelihood HMM estimator produces the correct second moment of the data, and the results can be extended to higher moments. [ABSTRACT FROM AUTHOR]

Visualizations often appear in multiples, either in a single display (e.g., small multiples, dashboard) or across time or space (e.g., slideshow, set of dashboards). However, existing visualization design guidelines typically focus on single rather than multiple views. Solely following these guidelines can lead to effective yet inconsistent views (e.g., the same field has different axes domains across charts), making interpretation slow and error-prone. Moreover, little is known how consistency balances with other design considerations, making it difficult to incorporate consistency mechanisms in visualization authoring software. We present a wizard-of-oz study in which we observed how Tableau users achieve and sacrifice consistency in an exploration-to-presentation visualization design scenario. We extend (from our prior work) a set of encoding-specific constraints defining consistency across multiple views. Using the constraints as a checklist in our study, we observed cases where participants spontaneously maintained consistent encodings and warned cases where consistency was overlooked. In response to the warnings, participants either revised views for consistency or stated why they thought consistency should be overwritten. We categorize participants' actions and responses as constraint validations and exceptions, depicting the relative importance of consistency and other design considerations under various circumstances (e.g., data cardinality, available encoding resources, chart layout). We discuss automatic consistency checking as a constraint-satisfaction problem and provide design implications for communicating inconsistencies to users. [ABSTRACT FROM PUBLISHER]

A novel visual object tracking method based on consistency-constrained nonnegative coding (CNC) is proposed in this paper. For the purpose of computational efficiency, superpixels are first extracted from each observed video frame. And then CNC is performed based on those obtained superpixels, where the locality on manifold is preserved by enforcing the temporal and spatial smoothness. The coding result is achieved via an iterative update scheme, which is proved to converge. The proposed method enhances the coding stability and makes the tracker more robust for object tracking. The tracking performance has been evaluated based on ten challenging benchmark sequences involving drastic motion, partial or severe occlusions, large variation in pose, and illumination variation. The experimental results demonstrate the superior performance of our method in comparison with ten state-of-art trackers. [ABSTRACT FROM PUBLISHER]

With the increasing need to construct long-term climate-quality data records to understand, monitor, and predict climate variability and change, it is vital to continue systematic satellite measurements along with the development of new technology for more quantitative and accurate observations. The Suomi National Polar-orbiting Partnership mission provides continuity in monitoring the Earth's surface and its atmosphere in a similar fashion as the heritage MODIS instruments onboard the National Aeronautics and Space Administration's Terra and Aqua satellites. In this paper, we aim at quantifying the consistency of Aqua MODIS and Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Reflectance (LSR) and NDVI products as related to their inherent spatial sampling characteristics. To avoid interferences from sources of measurement and/or processing errors other than spatial sampling, including calibration, atmospheric correction, and the effects of the bidirectional reflectance distribution function, the MODIS and VIIRS LSR products were simulated using the Landsat-8's Operational Land Imager (OLI) LSR products. The simulations were performed using the instruments' point spread functions on a daily basis for various OLI scenes over a 16-day orbit cycle. It was found that the daily mean differences due to discrepancies in spatial sampling remain below 0.0015 (1%) in absolute surface reflectance at subgranule scale (i.e., OLI scene size). We also found that the MODIS–VIIRS product intercomparisons appear to be minimally impacted when differences in the corresponding view zenith angles (VZAs) are within the range of -\!\!15^\circ to -35^\circ (\textrmVZAV-\textrmVZAM), where VIIRS and MODIS footprints resemble in size. In general, depending on the spatial heterogeneity of the OLI scene contents, per-grid-cell differences can reach up to 20%. Further spatial analysis of the simulated NDVI and LSR products revealed that, depending on the user accuracy requirements for product intercomparisons, spatial aggregations may be used. It was found that if per-grid-cell differences on the order of 10% (in LSR or NDVI) are tolerated, the product intercomparisons are expected to be immune from differences in spatial sampling. [ABSTRACT FROM PUBLISHER]

Modern replicated data stores aim to provide high availability, by immediately responding to client requests, often by implementing objects that expose concurrency. Such objects, for example, multi-valued registers (MVRs), do not have sequential specifications. This paper explores a recent model for replicated data stores that can be used to precisely specify causal consistency for such objects, and liveness properties like eventual consistency, without revealing details of the underlying implementation. The model is used to prove the following results: 1) An eventually consistent data store implementing MVRs cannot satisfy a consistency model strictly stronger than observable causal consistency ( \mathcal OCC ). \mathcal OCC is a model somewhat stronger than causal consistency, which captures executions in which client observations can use causality to infer concurrency of operations. This result holds under certain assumptions about the data store. 2) Under the same assumptions, an eventually consistent and causally consistent replicated data store must send messages of size linear in the size of the system: If s objects, each \Omega (\mathrm{lg} k) -bit in size, are supported by n$ replicas, then there is an execution in which an \Omega (\min \lbrace n,s\rbrace \mathrm{lg} k) -bit message is sent. [ABSTRACT FROM AUTHOR]

Preference structures, such as fuzzy preference relations, incomplete fuzzy preference relations, utility values, and preference orderings, are very useful in depicting the decision makers’ preferences over the considered objects in group decision making. They have been attracting great interest from both researchers and practitioners in recent decades. An important issue on these preference structures is to investigate the techniques of deriving priority weights of the objects from them. In this paper, based on generalized multiplicative consistency, we establish a general nonlinear optimization model with fuzzy preference relations, incomplete fuzzy preference relations, utility values, and preference orderings. By solving the model, we get a system of nonlinear equations and prove the uniqueness of its solution. Then, a convergent iterative algorithm is devised to derive the priority weights from this system of equations. The model and the algorithm include a variety of special cases suitable for group decision making with one or several of the aforementioned preference structures. A practical case illustration concerning a manufacturing company that is searching for the best compression ignition engine design is provided, and the numerical results of the developed models and the algorithm and the existing ones are also compared and analyzed in order to demonstrate the advantages and practicality of our models and algorithm. [ABSTRACT FROM AUTHOR]

A set of views defined by selection queries splits a database relation into sub-relations, each containing a subset of the original rows. This decomposition into horizontal fragments is lossless when the initial relation can be reconstructed from the fragments by union. In this paper, we consider horizontal decomposition in a setting where some of the attributes in the database schema are interpreted over a specific domain, on which a set of special predicates and functions is defined. We study losslessness in the presence of integrity constraints on the database schema. We consider the class of conditional domain constraints (CDCs), which restrict the values that the interpreted attributes may take whenever a certain condition holds on the non-interpreted ones, and investigate lossless horizontal decomposition under CDCs in isolation, as well as in combination with functional and unary inclusion dependencies. [ABSTRACT FROM AUTHOR]

The intuitionistic fuzzy preference relation (IFPR), whose elements are intuitionistic fuzzy values (IFVs), is more powerful than the traditional multiplicative preference relation and the fuzzy preference relation in expressing comprehensive preference information of a decision maker. The aim of this paper is to investigate a new approach to derive the priority weights from an IFPR. To do so, we give a new definition of multiplicative consistent IFPR, which is based on the membership and nonmembership degrees of the intuitionistic fuzzy judgments. After that, a formula, which involves the underlying intuitionistic fuzzy weights of the IFPR, is proposed to construct such a multiplicative consistent IFPR. Based on the formula, some fractional programming models are built to generate the intuitionistic fuzzy priority weighting vector of the IFPR. Several numerical examples are given to illustrate the validity and applicability of the proposed method. [ABSTRACT FROM AUTHOR]

The backup taken of a file system must be consistent, preserving data integrity across files in the file system. With file system sizes getting very large, and with demand for continuous access to data, backup has to be taken when the file system is active (is online). Arbitrarily taken online backup may result in an inconsistent backup copy. We propose a scheme referred to as mutual serializability to take a consistent backup of an active file system assuming that the file system supports transactions. The scheme extends the set of conflicting operations to include read-read conflicts, and it is shown that if the backup transaction is mutually serializable with every other transaction individually, a consistent backup copy is obtained. The user transactions continue to serialize within themselves using some standard concurrency control protocol such as Strict 2PL. We put our scheme into a formal framework to prove its correctness, and the formalization as well as the correctness proof are independent of the concurrency control protocol used to serialize user transactions. The scheme has been implemented and experiments show that consistent online backup is possible with reasonable overhead. [ABSTRACT FROM AUTHOR]

A distributed virtual environment (DVE) is a shared virtual environment (VE) that allows remote users to interact with each other through networks. DVEs are becoming very popular due to some prominent applications, such as online games and virtual worlds. To support a large number of users, a multi-server DVE architecture may be adopted, with each server managing a subset of users. However, there are two critical problems with this architecture: view inconsistency caused by delays and server overloading caused by uneven distribution of users. While the first problem affects users' perception of the VE and causes user disputes, the second problem affects the system response time. In this paper, we first show that the view inconsistency problem and the load balancing problem are conflicting objectives. We then propose an efficient joint optimization framework to address both problems. Our results show that the proposed method can improve the view inconsistency problem significantly, which is important to the interactivity of DVE applications. [ABSTRACT FROM PUBLISHER]

Hardware Trojans (HTs) have become a major concern in the modern integrated circuit (IC) industry, especially with the fast growth in IC outsourcing. HT detection and diagnosis are challenging due to the huge number of gates in modern IC designs and the high cost of testing. We propose a scalable and efficient HT detection and diagnosis scheme based on segmentation and consistency analysis of gate-level properties. In addition, we employ a self-consistency-based approach, where we conduct variable elimination and create subsegments from a fixed set of power measurements of the entire IC to minimize the number of power measurements. We evaluate our HT detection and diagnosis schemes on a set of ISCAS and ITC benchmarks. [ABSTRACT FROM AUTHOR]