ppxscal/embedding_network huggingface dataset:
The sequential sum problem and performance bounds on the greedy algorithm for the on-line Steiner problem
Authors: Zevi Miller, Dan Pritikin, Manley Perkel, I. H. Sudborough
Venue: Networks (2005)

This article is motivated by versions of the dynamic or on-line Steiner tree problem (OST) introduced by Imase and Waxman [4]. In this problem one is given an edge-weighted graph G and a sequence &sigma; = (x1, ,xn) of distinct vertices of G. The requirement is to construct for each i &le; n a tree Ti spanning the first i vertices of &sigma; subject to the condition that Ti-1ETi for all i, where Ti is constructed without knowledge of the remaining vertices xj, j > i. The goal of the on-line Steiner problem is to minimize the performance ratio; that is, the maximum (over 1 &le; i &le; n) of the ratio of the weight of Ti to the weight of the minimum weight tree in G spanning the first i vertices (the latter tree is called the Steiner tree for these vertices). In [4] a lower bound of 1 + &frac12;&lfloor; log2(n-1)&rfloor; was proved for this ratio. The authors further made the interesting conjecture that there is some on-line algorithm for the OST whose performance ratio achieves this lower bound. We show that a strong form of the greedy algorithm achieves a ratio that converges to the conjectured &frac12;log2(k) + O(1) as the proportion of degree 2 vertices in the instance graph grows. Our results also imply improvements in certain cases on the known upper bound &lceil;log2(n)&rceil; for the performance ratio of the greedy algorithm. Our approach is to study a related graph parameter. For each sequence &sigma; as above, define the associated cost $$L(\sigma) = \sum_{i = 2}^n c(i,\sigma),$$ where c(i,&sigma;) = min1 &le; t < idist(xi, xt). Then let Opt(n, G) be the maximum of L(&sigma;) over all such sequences &sigma; of length n. The problem of, given n and G, determining Opt(n, G) we call the Sequential Sum Problem (SSP). In this article we analyze the SSP, obtaining exact values and bounds on Opt(n, G) and relating these bounds to the greedy algorithm for the OST. For example, we calculate Opt(n, P) for the path P, and obtain a surprising characterization of all length n sequences &sigma; which realize Opt(n, P). By analyzing Opt(n, P) for the continuous path, we derive upper bounds on the performance ratio of the greedy algorithm for the OST in arbitrary graphs. On the other hand, generalizing the lower bound argument of [4] we show that there are instances of OST, which can significantly fool any on-line algorithm for OST. Specifically, given any tree T normalized to have total edge weight 1, we construct a graph G and a length k &le; |V(T)| sequence &sigma; of vertices of G for which the performance ratio of any on-line algorithm for the OST with input &sigma; is lower bounded by Opt(k, T). Finally, we show that the SSP for arbitrary G is NP-complete. &copy; 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(3), 143164 2005
Database Architectures for New Hardware
Authors: Anastassia Ailamaki
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

Thirty years ago, DBMS stored data on disks and cached recently used data in main memory buffer pools, while designers worried about improving I/O performance and maximizing main memory utilization. Today, however, databases live in multi-level memory hierarchies that include disks, main memories, and several levels of processor caches. Recent research shows that database performance is directly influenced by all levels of the underlying computer hardware and devices. This tutorial aims at (a) explaining why database performance depends on modern processor and memory microarchitectures, (b) surveying and contrasting research on the topic over the past decade, and (c) discussing future research challenges.
On Discovery of Extremely Low-Dimensional Clusters Using Semi-Supervised Projected Clustering
Authors: Kevin Y. Yip, David W. Cheung, Michael K. Ng
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

Recent studies suggest that projected clusters with extremely low dimensionality exist in many real datasets. A number of projected clustering algorithms have been proposed in the past several years, but few can identify clusters with dimensionality lower than 10% of the total number of dimensions, which are commonly found in some real datasets such as gene expression profiles. In this paper we propose a new algorithm that can accurately identify projected clusters with relevant dimensions as few as 5% of the total number of dimensions. It makes use of a robust objective function that combines object clustering and dimension selection into a single optimization problem. The algorithm can also utilize domain knowledge in the form of labeled objects and labeled dimensions to improve its clustering accuracy. We believe this is the first semi-supervised projected clustering algorithm. Both theoretical analysis and experimental results show that by using a small amount of input knowledge, possibly covering only a portion of the underlying classes, the new algorithm can be further improved to accurately detect clusters with only 1% of the dimensions being relevant. The algorithm is also useful in getting a target set of clusters when there are multiple possible groupings of the objects.
A clustered tree method for implementing application level multicast
Authors: Xue Bai, Ade G. Ola, Yinjing Cui, Fidelis Ikem
Venue: Proceedings of the 2004 international symposium on Information and communication technologies (2004)

In this paper, we present a clustered tree-based protocol for constructing efficient overlay structure for application-level multicast. Unlike existing approaches, the constructed clustered multicast trees do not depend solely on the underlying network communications but also on the bandwidth required by the application. In the constructed tree, end hosts are clustered into appropriate groups based on a predefined threshold for unicast latency. In any given cluster, every host-except for one that is responsible for connecting to other cluster- has a parent in that cluster. The buffer at each host is used to control how many clients a host can handle; this determines the bandwidth at the host. Clusters are connected to each other based on minimum unicast latency rule. The result shows that the protocol constructs an optimized topology to reflect the bandwidth required for a given data dissemination rate. It also minimizes the maximum delay to deliver data packets from source to all recipients.
Balance of Power: Dynamic Thermal Management for Internet Data Centers
Authors: Ratnesh K. Sharma, Cullen E. Bash, Chandrakant D. Patel, Richard J. Friedrich, Jeffrey S. Chase
Venue: IEEE Internet Computing (2005)

The advent of Internet-based applications and their resulting multitier distributed architecture has changed the focus of design for large-scale Internet computing. Internet server applications execute in a horizontally scalable topology across hundreds or thousands of commodity servers in an Internet data center. Increasing scale and power density have a significant impact on the data center's thermal properties. Effective thermal management is essential to the robustness of mission-critical applications. Internet service architectures can address multisystem resource management and thermal management at the granularity of data centers. This article presents a framework for thermal-load balancing by applying load monitoring and dynamic workload placement to manage the thermal distribution within a data center. The results demonstrate that dynamic thermal management based on asymmetric workload placement can promote uniform temperature distribution that reduces local hot spots, quickly responds to thermal emergencies, reduces energy consumption costs, reduces initial cooling system capital costs and improves equipment reliability.
EXPERIMENTAL EVALUATION OF ICON QUALITY
Authors: Paul F. Sorenson, Jayson M. Webb
Venue: ACM SIGCHI Bulletin (1991)

There are currently no standard methods to assess and ensure the usability of graphical user interfaces (GUIs). A series of experiments were designed to measure the factors that affect the usability of a common element of GUIs, icons. A procedure for designing effective iconic images based on our results with subjects from widely varying educational and computer backgrounds is described.
Forth and AI revisited: BRAIN.FORTH
Authors: Paul Frenger
Venue: ACM SIGPLAN Notices (2004)

Six years ago in this journal we discussed the work of Arthur T. Murray, who endeavored to explore artificial intelligence using the Forth programming language [1]. His creation, which he called MIND.FORTH, was interesting in its ability to understand English sentences in the form: subject-verb-object. It also had the capacity to learn new things and to form mental associations between recent experiences and older memories. In the intervening years, Mr. Murray has continued to develop his MIND.FORTH: he has translated it into Visual BASIC, PERL and Javascript, he has written a book [2] on the subject, and he maintains a wiki web site where anyone may suggest changes or extensions to his design [3]. MIND.FORTH is necessarily complex and opaque by virtue of its functionality; therefore it may be challenging for a newcomer to grasp. However, the more dedicated student will find much of value in this code. Murray himself has become quite a controversial figure.
Modified Radix-2 Montgomery Modular Multiplication to Make It Faster and Simpler
Authors: Kooroush Manochehri, Saadat Pourmozafari
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume I - Volume 01 (2005)

Montgomery modular multiplication algorithm is commonly used in implementations of the RSA cryptosystem or other cryptosystems based on modular arithmetic. There are several improvements for making it suitable for hardware implementation. Radix-2 version of this algorithm is simple and fast to implement in hardware design. In this paper a new algorithm based on this approach is presented that is more simple and faster than radix-2 algorithm. For implementing this new algorithm, carry save adder (CSA) architecture is used and synthesized in both ASIC and FPGA technology.
Consensus algorithms for the generation of all maximal bicliques
Authors: Gabriela Alexe, Sorin Alexe, Yves Crama, Stephan Foldes, Peter L. Hammer, Bruno Simeone
Venue: Discrete Applied Mathematics (2004)

We describe a new algorithm for generating all maximal bicliques (i.e. complete bipartite, not necessarily induced subgraphs) of a graph. The algorithm is inspired by, and is quite similar to, the consensus method used in propositional logic. We show that some variants of the algorithm are totally polynomial, and even incrementally polynomial. The total complexity of the most efficient variant of the algorithms presented here is polynomial in the input size, and only linear in the output size. Computational experiments demonstrate its high efficiency on randomly generated graphs with up to 2000 vertices and 20,000 edges.
Language Systems, Inc.: MUC-4 test results and analysis
Authors: Christine A. Montgomery, Bonnie Glover Stalls, Robert E. Stumberger, Naicong Li, Robert S. Belvin, Alfredo Arnaiz, Susan B. Hirsh
Venue: Proceedings of the 4th conference on Message understanding (1992)

LSI's overall natural language processing (NLP) objective is the development of a broad coverage, reusable system which is readily transportable to additional domains, applications, and sublanguages in English, as well as providing a foundation for our multilingual work. Our system, called DBG, for Data Base Generator, is comprised of a set of NLP components which have been developed, extended, and rebuilt over a period of some years. The core of the system is an innovative Principle-based parser, using ideas from [1], which we began developing in the course of MUC-3 to replace our previous chart parser. Our approach thus relies on the concept of powerful, robust parsing as the most crucial component in an NLP system. In applying our NLP system to text extraction, our ultimate objective is to develop a high quality text extraction system, where "high quality" is defined as scoring above 80% -- a number well beyond any current MUC scores.
Advanced Algorithms for Autonomous Hyperspectral Change Detection
Authors: A. Schaum, Alan Stocker
Venue: Proceedings of the 33rd Applied Imagery Pattern Recognition Workshop (2004)

Persistent ISR (Intelligence Surveillance and Reconnaissance) has proven its value as a tactic for national defense. This activity can collect, in particular, information necessary for executing an important Concept of Operations: Widearea autonomous change detection over long time intervals. Here we describe the remarkable potential of hyperspectral remote sensing systems for enabling such missions, using either visible or thermal infrared wavelengths. First we describe blind change detection, in which no target knowledge is assumed. Targets that have moved can nevertheless be distinguished from naturally occurring background radiometric changes through the use of multivariate statistics informed by simple physics. Detection relies on the ability of hyperspectral algorithms to predict certain conserved properties of background spectral patterns over long time intervals. We also describe a method of mitigating the most worrisome practical engineering difficulty in pixel-level change detection, image misregistration. This has led, in turn, to a method of estimating spectral signature evolution using multiplescene statistics. Finally, we present a signature-based detection technique that fuses two discrimination mechanisms: use of some prior knowledge of target spectra, and the fact that a change has occurred.
Towards an Indoor Location System Using RF Signal Strength in IEEE 802.11 Networks
Authors: Adam Harder, Lanlan Song, Yu Wang
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume II - Volume 02 (2005)

Location is one of the most important contexts used in pervasive computing environments. GPS systems are intensely used to detect the location information; they mainly work in outdoor environment. Applications call for precise, easy-to-build, and easy-to-use in-door location systems. This paper presents our work to implement an indoor location determination system for Microsoft-Windows-based platforms using a pre-existing IEEE 802.11 wireless network.The location is determined from radio signal strength information collected from multiple base stations at different physical locations. Our experiments show a high accuracy rate of this approach.
A modeling approach to uncover hyperlink patterns: the case of Canadian universities
Authors: Liwen Vaughan, Mike Thelwall
Venue: Information Processing and Management: an International Journal (2005)

Hyperlink patterns between Canadian university Web sites were analyzed by a mathematical modeling approach. A multiple regression model was developed which shows that faculty quality and the language of the university are important predictors for links to a university Web site. Higher faculty quality means more links. French universities received lower numbers of links to their Web sites than comparable English universities. Analysis of interlinking between pairs of universities also showed that English universities are advantaged. Universities are more likely to link to each other when the geographical distance between them is less than 3000 km, possibly reflecting the east vs. west divide that exists in Canadian society.
Automatic Measurement of a QoS Metric for Web Service Recommendation
Authors: Niko Thio, Shanika Karunasekera
Venue: Proceedings of the 2005 Australian conference on Software Engineering (2005)

Web Services have enabled businesses and organizations to collaborate without platform interoperability and programming language barriers. Quality of Service (QoS) of a web service is an important factor that differentiates similar services offered by different service providers. Such a measure would allow web service clients to choose and bind to a suitable web service at run time (based on QoS attributes). Some researchers have proposed the integration of the QoS measure on the web service directory server. However, a mechanism to maintain the QoS metric has not been defined yet. In this paper, we propose such a mechanism. This mechanism involves automated measurement of QoS attributes on both the client and provider sides, when the service is being used, and updating the QoS-aware web services directory with this information. We describe a prototype we developed for this purpose and present the results of using this prototype for gathering QoS measurements at run time.
Persistence in web based collaborations
Authors: N. Bryan-Kinns, P. G. T. Healey, J. Lee
Venue: Special interest tracks and posters of the 14th international conference on World Wide Web (2005)

We outline work on web based support for group creativity. We focus on a study of the effect persistence of participants' musical contributions has on their mutual engagement.
Rate-adaptive time synchronization for long-lived sensor networks
Authors: Saurabh Ganeriwal, Deepak Ganesanl, Mark Hansen, Mani B. Srivastava, Deborah Estrin
Venue: Proceedings of the 2005 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2005)

Time synchronization is critical to sensor networks at many layers of its design and enables better duty-cycling of the radio, accurate localization, beamforming and other collaborative signal processing. While there has been significant work in sensor network synchronization, measurement based studies have been restricted to very short-term (few minutes) datasets and have focused on obtaining accurate instantaneous synchronization. Long-term synchronization has typically been handled by periodic re-synchronization schemes with beacon intervals of a few minutes based on the assumption that long-term drift is too hard to model and predict. Thus, none of this work exploits the temporally correlated behavior of the clock drift. Yet, there are incredible energy gains to be achieved from better modeling and prediction of long-term drift that can provide bounds on long-term synchronization error across a sensor network. Better synchronization can lead to significantly lower duty-cycles of the radio, simplify signal processing and can enable an order of magnitude greater lifetime than current techniques.We measure, evaluate and analyze in-depth the long-term behavior of synchronization skew and drift on typical Mica sensor nodes and develop an efficient long-term time synchronization protocol. We use four real time data sets gathered over periods of 12-30 hours in different environmental conditions to study the interplay between three key parameters that influence long-term synchronization - synchronization rate, history of past synchronization beacons and the estimation scheme. We use this measurement-based study to design an online adaptive time-synchronization algorithm that can adapt to changing clock drift and environmental conditions while achieving application-specified precision with very high probability. We find that our algorithm achieves between one and two orders of magnitude improvement in energy efficiency over currently available time-synchronization approaches.
Performance evaluation of market-based resource allocation for Grid computing: Research Articles
Authors: J. Gomoluch, M. Schroeder
Venue: Concurrency and Computation: Practice Experience (2004)

Resource allocation is an important aspect of Grid computing. Over the past few years, various systems have been developed which use market mechanisms to allocate resources. However, the performance of such policies has not been sufficiently studied. In this paper, we investigate under which circumstances market-based resource allocation by continuous double auctions and by the proportional share protocol, respectively, outperforms a conventional round-robin approach. We develop a model for clients, servers and the market, and present simulation results. Factors which are studied include the amount of load in the system, the number of resources, different degrees of resource heterogeneity, and communication delays. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Rcast: A Randomized Communication Scheme for Improving Energy Efficiency in MANETs
Authors: Sunho Lim, Chansu Yu, Chita R. Das
Venue: Proceedings of the 25th IEEE International Conference on Distributed Computing Systems (2005)

In a typical wireless mobile ad hoc network (MANET) using a shared communicationmedium, every node receives or overhears every data transmission occurring in its vicinity. However, this technique is not applicable when a power saving mechanism (PSM) such as the one specified in IEEE 802.11 is employed, where a packet advertisement period is separated from the actual data transmission period.When a node receives an advertised packet that is not destined to itself, it switches to a low-power state during the data transmission period, and thus, conserves power. However, since some MANET routing protocols such as Dynamic Source Routing (DSR) collect route information via overhearing, they would suffer if they are used with the IEEE 802.11 PSM. Allowing no overhearing may critically deteriorate the performance of the underlying routing protocol, while unconditional overhearing may offset the advantage of using PSM. This paper proposes a new communication mechanism, called RandomCast or Rcast, via which a sender can specify the desired level of overhearing in addition to the intended receiver. Therefore, it is possible that only a random set of nodes overhear and collect route information for future use. Rcast improves not only the energyefficiency, but also the energy balance among the nodes, without significantly affecting the routing efficiency. Extensive simulation using the ns-2 network simulator shows that Rcast is highly energy-efficient compared to the original IEEE 802.11 PSM and On-Demand Power Management (ODPM) protocol in terms of total energy consumption (157% to 236% less than PSM and 28% to 131% less than ODPM) and energy balance (four times less variance than ODPM) among the nodes.
Eulerian subgraphs and Hamilton-connected line graphs
Authors: Dengxin Li, Hong-Jian Lai, Mingquan Zhan
Venue: Discrete Applied Mathematics (2005)

Let C(l,k) denote a class of 2-edge-connected graphs of order n such that a graph G ∈ C(l,k) if and only if for every edge cut S ⊆ E(G) with |S| ≤ 3, each component of G-S has order at least (n-k)/l. We prove the following: (1) If G ∈ C(6,0), then G is supereulerian if and only if G cannot be contracted to K2,3, K2,5 or K2,3(e), where e ∈ E(K2,3) and K2,3(e) stands for a graph obtained from K2,3 by replacing e by a path of length 2. (2) If G ∈ C(6, 0) and n≥7, then L(G) is Hamilton-connected if and only if κ(L(G))≥3. Former results by Catlin and Li, and by Broersma and Xiong are extended.