Miracle-dz/UniFAR-FTUs huggingface dataset:
Approximation algorithms for facility location problems (extended abstract)

We present new approximation algorithms for several facility location problems. In each facility location problem that we study, there is a set of locations at which we may build a facility (such as a warehouse), where the cost of building at location i is fi; furthermore, there is a set of client locations (such as stores) that require to be serviced by a facility, and if a client at location j is assigned to a facility at location i , a cost of cij is incurred. The objective is to determine a set of locations at which to open facilities so as to minimize the total facility and assignment costs. In the uncapacitated case, each facility can service an unlimited number of clients, whereas in the capacitated case, each facility can serve, for example, at most u clients. These models and a number of closely related ones have been studied extensively in the Operations Research literature. We shall consider the case in which the assignment costs are symmetric and satisfy the triangle inequality. For the uncapacitated facility location, we give a polynomial-time algorithm that (cid:12)nds a solution within a factor of 3.16 of the optimal. This is the (cid:12)rst constant performance guarantee known for this problem. We also present approximation algorithms with constant performance guarantees for a number of capacitated models as well as a generalization in which there is a 2-level hierarchy of facilities. Our results are based on the (cid:12)ltering and rounding technique of Lin & Vitter. We also give a randomized variant of this technique that can then be derandomized to yield improved performance guarantees.
An Event-based Communication Concept for Human Supervision of Autonomous Robot Teams

The supervisor's understanding about the status of the robots and the mission is a crucial factor in supervisory control, because it influences all decisions and actions of the human in charge. In this paper, the concept of situation overview (SO) is presented as an adequate knowledge base for a human supervisor of an autonomous robot team. SO consists of knowledge about each individual robot (robot SO) and overview of team coordination and the actions towards mission achievement (mission SO). It provides the human with relevant information to control a robot team with high-level commands, e. g. , by adapting mission details and influencing task allocation in a manner that is applicable to different task allocation methods in general. The presented communication concept to obtain SO is based on events, that are detected using methods from complex event processing. These events are dynamically tagged to different semantical or functional topics, and are sent to the supervisor either as notifications of different levels, to inform the supervisor about the mission progress, unexpected events and errors, or as queries, to transfer decisions to the supervisor, to make use of implicit knowledge and the human's experience in critical situations. The robots' level of autonomy can be adapted using policies, that allow to take decisions either autonomously by the robots, or with support by the supervisor, using different query modes. The concept can be applied to fundamentally different problem classes involving autonomous robot teams and a remote human supervisor. The application of the concept is discussed for the two example scenarios of urban search and rescue and robot soccer.
PEL: Position-Enhanced Length Filter for Set Similarity Joins

Set similarity joins compute all pairs of similar sets from two collections of sets. Set similarity joins are typically implemented in a lter-verify framework: a lter generates candidate pairs, possibly including false positives, which must be veried to produce the nal join result. Good lters produce a small number of false positives, while they reduce the time they spend on hopeless candidates. The best known algorithms generate candidates using the so-called prex lter in conjunction with length- and position-based lters. In this paper we show that the potential of length and position have only partially been leveraged. We propose a new lter, the position-enhanced length lter , which exploits the matching position to incrementally tighten the length lter; our lter identies hopeless candidates and avoids processing them. The lter is very ecient,
Understanding control flow transfer and its predictability in java processing

An in-depth look and understanding of control flow transfer arid its predictability can guide architects to adapt control flow prediction hardware in Java processing or finely tune the performance of JVM sojhare.on general purpose machines. To our knowledge, this paper provides the first insight of branch behavior on a standard Java Virtual Machine with real workloads. Employing a complete system simulation environment, we profile brunch execution characteristics and quantify the performance of a wide range of prediction schemes on both user and kernel code. The impact of different JVM styles (JIT compiler and interpreter) on branch behavior is also studied. We firid that: (I) Kernel branches constitute a significant portion of total branch execution in Java processing; (2) Kernel and user code favor different prediction mechanisms; (3) Java processing exercises fairly large number of branch sites and large control flow footprint compared with the execution of benchmarks such us SPEClnt95; (4) A major part of the dynamic indirect branches are multiple target (polymorphic) brunches. Target addresses of indirect branches, especially those in interpreting mode are highly interleaved and cause high BTB tiiisprediction.
On the role of robot configuration in Cartesian stiffness control

The stiffness ellipsoid, i.e. the locus of task-space forces obtained corresponding to a deformation of unit norm in different directions, has been extensively used as a powerful representation of robot interaction capabilities. The size and shape of the stiffness ellipsoid at a given end-effector posture are influenced by both joint control parameters and - for redundant manipulators - by the chosen redundancy resolution configuration. As is well known, impedance control techniques ideally provide control parameters which realize any desired shape of the Cartesian stiffness ellipsoid at the end-effector in an arbitrary non-singular configuration, so that arm geometry selection could appear secondary. This definitely contrasts with observations on how humans control their arm stiffness, who in fact appear to predominantly use arm configurations to shape the stiffness ellipsoid. To understand this discrepancy, we provide a more complete analysis of the task-space force/deformation behavior of redundant arms, which explains why arm geometry also plays a fundamental role in interaction capabilities of a torque controlled robot. We show that stiffness control of realistic robot models with bounds on joint torques can't indeed achieve arbitrary stiffness ellipsoids at any given arm configuration. We first introduce the notion of maximum allowable Cartesian force/displacement (“stiffness feasibility”) regions for a compliant robot. We show that different robot configurations modify such regions, and explore the role of different configurations in defining the performance limits of Cartesian stiffness controllers. On these bases, we design a stiffness control method that suitably exploits both joint control parameters and redundancy resolution to achieve desired task-space interaction behavior.
Wide-Field OCT Angiography at 400 KHz Utilizing Spectral Splitting

Optical angiography systems based on optical coherence tomography (OCT) require dense sampling in order to maintain good vascular contrast. We demonstrate a way to gain acquisition speed and spatial sampling by using spectral splitting with a swept source OCT system. This method splits the recorded spectra into two to several subspectra. Using continuous lateral scanning, the lateral sampling is then increased by the same factor. This allows increasing the field of view of OCT angiography, while keeping the same transverse resolution and measurement time. The performance of our method is demonstrated in vivo at different locations of the human retina and verified quantitatively. Spectral splitting can be applied without any changes in the optical setup, thus offering an easy way to increase the field of view of OCT in general and in particular for OCT angiography.
Synchronization in Complex Dynamical Networks

Excitatory recurrent networks, while confirmed in theory, have not been intensely studied by simulation focused on synchronization properties. In our research, we validate on the basis of complex network models, the refinement of degree and link-level deepness, which embodies principles of topological structural nature with emphasis on the relationship between the topology and the dynamics of such complex networks. Biologically plausible excitatory networks that are maintaining this structure, develop a stable synchronized pattern of activity depending on spontaneous activity and synaptic refractoriness. We show that by fixed synaptic weights the synchronous bursts of oscillatory activity are stable and involve the whole network. As a result, by investigating conditions for synchronized oscillatory activity in several types of networks, we found that 'small world' networks with a higher proportion of long connections can sustain a higher degree of synchronization
Comparative simulation of conventional maximum power point tracking methods

Maximum power point tracking (MPPT) is an key component of photovoltaic system so as to maximise the energy under given specified condition. Perturb and observe (P&O) and incremental conductance(IC) are two popular conventional control algorithm because of the simplicity in design. In this work, comparisons between these two conventional algorithms are carried out. These algorithms are implemented in MATLAB/Simulink environment considering the specifications of Solarex MSX-64 model. Double diode model of the solar cell is considered for the experimentation. The results of simulation are compared and discussed in detail.
Identification of green, yellow and red legacy components

Software systems are often getting older than expected, and it is a challenge to try to make sure that they grow old gracefully. This implies that methods are needed to ensure that system components are possible to maintain. In this paper, the need to investigate, classify and study software components is emphasized. A classification method is proposed. It is based on classifying the software components into green, yellow and red components. The classification scheme is complemented with a discussion of suitable models to identify problematic components. The scheme and the models are illustrated in a minor case study to highlight the opportunities. The long term objective of the work is to define methods, models and metrics which are suitable to use in order to identify software components which have to be taken care of through either tailored processes (e.g. additional focus on verification and validation) or reengineering. The case study indicates that the long term objective is realistic and worthwhile.
Source address validation solution with OpenFlow/NOX architecture

Current Internet is lack of validation on source IP address, resulting in many security threats. The future Internet can face the similar routing locator spoofing problem without careful design. The current in-progress source address validation standard, i.e., SAVI, is not of enough protection due to the solution space constraint. In this article, a mechanism named VAVE is proposed to improve the SAVI solutions. VAVE employs OpenFlow protocol, which provides the de facto standard network innovation interface, to solve source address validation problem with a global view. Significant improvements can be found from our evaluation results.
The impact of parental characteristics and contextual effects on returns to the parental home in Britain

This paper uses successive cohorts of rising 16 year olds followed up within the British Household Panel Study to examine the importance of parental resources and parental family structure on the likelihood of young adults returning to the parental home following an initial departure. We also examine whether local area effects such as urbanicity, housing or labour market factors are significant. Our analyses of individuals aged 18-24 indicate that although parental background and circumstances can contribute to young adults’ propensity to return home, this is far outweighed by the impact of the individual-level characteristics of the young adults themselves. Of particular importance in promoting returns to the parental home are experiencing a change in economic activity,especially moving out of full-time education into unemployment, and experiencing a partnership dissolution. Whilst local house prices are shown to be related to the propensity to return home for women, most contextual factors are found to have little effect for either men or women.
Sink Location Service via Inner Rectangular in Wireless Sensor Networks

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires the source nodes to be aware of the location of the sink nodes. How source nodes efficiently obtain the sink location information has been merely studied yet. In this paper, we propose a Sink Location Service via Inner Rectangular in Wireless Sensor Networks. A source node and a sink node send location queries and location announcement messages to specified direction respectively by geographic routing; thus, a sink location query path and a sink location announcement path is generated. The node located on a crossing point of these two paths informs the source node about the sink location information. Then the source node sends data to the sink node by geographic routing. The proposed scheme constructs a virtual restricted linear flooding zone inside the network to guarantee the existence of the crossing point. Simulation results show that proposed scheme is reliable and efficient than the existing protocols.
Hybrid Visualization of Sparse Point-Based Data Using GPGPU

Direct point-based rendering is a popular method in scientific visualization, since the number of point-based datasets increased dramatically in the past few years. At the same time, rendering of point primitives is becoming less efficient as the data size increases. Point splatting, volume-based rendering, or is surface extraction are well-known approaches that can be utilized. Unfortunately, high visual accuracy is often sacrificed. Furthermore, unstructured sparse point-based data is more difficult to visualize, since no surface geometry and topology can be implicitly defined. This paper introduces a novel hybrid visualization method that utilizes point-based and volume-based rendering of sparse point-based data. The visualization is done entirely with a custom rendering pipeline by using GPGPU, which provides accelerated rendering. The method achieves real-time visualization, while retaining high visual accuracy, as shown on cosmological dark matter SPH-based dataset.
Traditional industrial economics and purchasing : atheoretical application of the SCP-paradigm on decision points in purchasing

This paper addresses Industrial Economics and its core model the SCP-paradigm. Furthermore the question was raised how Industrial Economics contributes to decision making in the purchasing year cycle. The link between the decision points in purchasing and Industrial Economics is made with help of the SCP-Paradigm. The findings in this paper provide insights for research and practice as to the relation between the market structure, firm’s conduct and firm’s performance. As well as how structure will affect behaviour and performance of firms and industries.
Selective labeling of spiral ganglion and granule cells with D- aspartate in the auditory system of cat and guinea pig

The present study sought to locate putative glutamatergic or aspartatergic pathways in the auditory system of cats and guinea pigs. We injected 0.06 to 3 mM D-[3H] aspartate (D-Asp) in the cochlear nucleus before preparation for light microscopic autoradiography. At short survival times (15 and 40 min) there was heavy labeling of astrocytic somata. Labeling patterns typical of cochlear nerve endings decorated neurons in the cochlear nucleus, e.g., cell bodies and dendritic trunks of octopus cells. Labeling patterns consistent with retrograde axonal transport by the parallel fibers of granule cells appeared in the molecular layer of the dorsal cochlear nucleus and in the external granular layer. Retrograde labeling of the cochlear nerve root fibers also occurred. Consistent with these results are companion biochemical findings on the rapidly dissected cochlear nuclei of guinea pigs. The dorsal, anteroventral, and posteroventral cochlear nuclei, each, evinced uptake of D-Asp. Subsequently, electrical stimulation of each nucleus released a portion of the accumulated amino acid. Most of this release probably came from synaptic endings. Another group of experiments compared autoradiographic localization of 0.06 to 3 mM D- Asp to that of horseradish peroxidase (HRP) 6 hr to 2 d after injections in the cochlear nucleus. Astroglial cell bodies were no longer labeled by D-Asp, but spiral ganglion cell bodies in the cochlea and granule cell bodies in the cochlear nucleus were. Perikarya of the periolivary and ventral cochlear nuclei projecting to the dorsal cochlear nucleus were labeled by HRP and not by D-Asp. Thus, comparisons with the HRP findings indicate that D-Asp labeling resulted from a selective retrograde transport. There was no evidence for a selective anterograde axonal transport. The present observations support the hypothesis that cochlear nerve fibers and granule cells may use L-glutamate and/or L-aspartate as a transmitter in the cochlear nucleus.
JPEG Compression Steganography & Crypography Using Image-Adaptation Technique

In any communication, security is the most important issue in today’s world. Lots of data security and data hiding algorithms have been developed in the last decade, which worked as motivation for our research. In this paper, named “JPEG Compression Steganography & Cryptography using Image-Adaptation Technique”, we have designed a system that will allow an average user to securely transfer text messages by hiding them in a digital image file using the local characteristics within an image. This paper is a combination of steganography and encryption algorithms, which provides a strong backbone for its security. The proposed system not only hides large volume of data within an image, but also limits the perceivable distortion that might occur in an image while processing it. This software has an advantage over other information security software because the hidden text is in the form of images, which are not obvious text information carriers. The paper contains several challenges that make it interesting to develop. The central task is to research available steganography and encryption algorithms to pick the one the offer the best combination of strong encryption, usability and performance. The main advantage of this project is a simple, powerful and user-friendly GUI that plays a very large role in the success of the application.
Linking mechanism supporting end-user computing

It is proposed that organizations better able to exploit information-related opportunities do so because their information systems groups provide a greater number of linking mechanisms through which end-user computing is motivated and facilitated. This study examines this notion. Interviews were held in 21 organizations to determine the extent to which 12 linking mechanisms were being used to facilitate 19 issues. An examination of the findings suggests that while the linking mechanisms are being used, this usage (1) is not yet that extensive and (2) the apparently more effective links are not always those most used.
Mediation and Strategic Militarization Adam Meirowitz

This paper challenges the received wisdom that mediation is a weak institution. Much of this perspective is supported by variations of three arguments. First, mediators often do not have access to privileged information, beyond what is relayed to them by disputants. Second, mediators recommendations need to be self-enforcing as they are not backed by appropriate enforcement institutions. Third, a mediator’s mandate is usually set within an already ongoing dispute, and does not include the long-term objective of preventing militarization. The first point has been taken to suggest that anything a disputant is willing to share with the mediator she would also be willing to share with an adversary. The second point limits the role of mediation to information sharing which is undermined by the first incentive, and the third raises the possibility that even if a mediator could improve on things in the shortrun, a time consistency problem would cause mediation to induce perverse incentives for militarization. We show that these concerns are misplaced in settings where the states posses private information about their own capacity to fight. We find that mediation turns out to be just as effective as a hypothetical optimal institution with strong enforcement power and the ability to internalizes the long-term consequences of its behavior on subsequent militarization decisions. Comparing mediation with the best possible unmediated peace talks we find that when militarization costs are relatively low, mediation strictly improves the equilibrium chances of peace. ∗Princeton University, Department of Politics. †Columbia University, Departments of Political Science and Economics. ‡Princeton University, Department of Politics. §Warwick University, Department of Economics.
Prefrontal Gamma Oscillations Encode Tonic Pain in Humans

Under physiological conditions, momentary pain serves vital protective functions. Ongoing pain in chronic pain states, on the other hand, is a pathological condition that causes widespread suffering and whose treatment remains unsatisfactory. The brain mechanisms of ongoing pain are largely unknown. In this study, we applied tonic painful heat stimuli of varying degree to healthy human subjects, obtained continuous pain ratings, and recorded electroencephalograms to relate ongoing pain to brain activity. Our results reveal that the subjective perception of tonic pain is selectively encoded by gamma oscillations in the medial prefrontal cortex. We further observed that the encoding of subjective pain intensity experienced by the participants differs fundamentally from that of objective stimulus intensity and from that of brief pain stimuli. These observations point to a role for gamma oscillations in the medial prefrontal cortex in ongoing, tonic pain and thereby extend current concepts of the brain mechanisms of pain to the clinically relevant state of ongoing pain. Furthermore, our approach might help to identify a brain marker of ongoing pain, which may prove useful for the diagnosis and therapy of chronic pain.
An intelligent tool for re-engineering software modularity

The author describes a software tool that provides heuristic modularization advice for improving existing code. A heuristic design similarity measure is defined, based on the Parna information hiding principle. The measure supports two services: clustering, which identifies groups of related procedures, and maverick analysis, which identifies individual procedures that appear to be in the wrong module. The tool has already provided useful advice in several real programming projects. The tool will soon incorporate an automatic tuning method, which allows the tool to learn from its mistakes, adapting its advice to the architect's preferences. A preliminary experiment demonstrates that the automatically tuned similarity function can assign procedures to modules very accurately. <<ETX>>