ppxscal/embedding_network huggingface dataset:
The climatological record of clear-sky longwave radiation at the Earth's surface: evidence for water vapour feedback?
Authors: F. Prata
Venue: International Journal of Remote Sensing (2008)

An increase in global surface temperature of between 1.4 K and 5.8 K is expected to occur by 2100 due to a doubling of the global concentration of CO2. Associated with this predicted surface warming will be an increase in the downwards longwave (3-100 µm) radiation (F↓) at the Earth's surface. Observations of this quantity on a global scale are almost non-existent. Clear-sky estimates of F↓ can be obtained from radiative transfer calculations using temperature and moisture profiles from radiosoundings. Here long-term (more than 25 years) mean monthly profiles obtained from globally distributed land-based radiosonde stations are subjected to detailed radiative transfer computations and Fourier time-series analysis. The results indicate that over the period 1964-1990, there has been a global increase in the clear-sky longwave flux at the surface. The global trend is approximately +1.7 W m-2 per decade, and there is a strong latitudinal pattern, with greater increases occurring in the tropics and smaller increases at both poles. There are also concomitant increases in precipitable water and the patterns appear to be highly correlated with increases in F↓. Increases in CO2 with time were not included in the calculations and it is estimated that the radiative impact of changes in CO2 on the F↓ trend is ∼20% per decade. A simple model of the dependence of surface air temperature and precipitable water on the downwards clear-sky flux supports the notion that both variables are contributing to increases in F↓. It is suggested that increases in precipitable water represent a positive feedback on F↓.
Annual and seasonal variations in tropospheric ozone concentrations around Varanasi
Authors: Supriya Tiwari, Richa Rai, Madhoolika Agrawal
Venue: International Journal of Remote Sensing (2008)

This study examines the annual, seasonal and diurnal variations in the ambient concentrations of ozone at a suburban site of Varanasi, India, during 2002-2006. Prominent seasonal variations in ozone concentrations were recorded. Ozone concentrations were higher during the warmer months. Daytime 12-hourly mean monthly ozone concentrations varied from 45.18 to 62.35 ppb during summer, from 28.55 to 44.25 ppb during winter and from 24 to 43.85 ppb during the rainy season from 2002 to 2006. Distinct diurnal variations in ozone concentrations were also observed. Daytime maxima in ozone concentration were recorded between 1200 and 1400 h, whereas morning and evening hours showed lower concentrations of ozone. Ozone concentrations in the atmosphere depended on several meteorological factors. Monthly average ozone concentration was significantly correlated with maximum temperature (p
Effect of 6MeV electron irradiation on electrical characteristics of the Au/n-Si/Al Schottky diode
Authors: E. Uğurel, Ş. Aydoğan, K. Şerifoğlu, A. Türüt
Venue: Microelectronic Engineering (2008)

Electron irradiation of the Au/n-Si/Al Schottky diode was performed by using 6MeV electrons and 3x10^1^2e^-/cm^2 fluency. The current-voltage (I-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) characteristics of the unirradiated and irradiated Schottky diode were analyzed. It was seen that the values of the barrier height, the series resistance, and the ideality factor increased after electron irradiation. However, there was a decrease in the leakage current with electron irradiation. The increase in the barrier height and in the series resistance values was attributed to the dopant deactivation in the near-interface region. The interface states, N"s"s, have been decreased significantly after electron irradiation. This was attributed to the decrease in recombination centre and the existence of an interfacial layer. A decrease in the capacitance was observed after electron irradiation. This was attributed to decrease in the net ionized dopant concentration with electron irradiation.
The symbolic OBDD scheme for generating mechanical assembly sequences
Authors: Tianlong Gu, Huadong Liu
Venue: Formal Methods in System Design (2008)

Assembly sequence planning is one of typical combinatorial optimization problems, where the size of parts involved is a significant and often prohibitive difficulty. The compact storage and efficient evaluation of feasible assembly sequences is one crucial concern. Ordered binary decision diagram (OBDD) is a canonical form to represent and manipulate the Boolean functions efficiently, and appears to give improved results for large-scale combinatorial optimization problems. In this paper, assembly knowledge models of liaison graph and translation function are formulated by OBDDs, and OBDD-based representation of assembly sequences is proposed. A novel OBDD-based procedure was presented to generate all geometrically feasible assembly sequences from the OBDDs of liaison graph and translation relation. This procedure can be used conveniently on the computer and all the feasible sequences can be derived. The great advantage of OBDD-based scheme is that the storage space of OBDD-based representation of feasible assembly sequences does not increase with the part count of assembly dramatically so quickly as that of AND/OR graph does. We developed the prototype tool for generating assembly sequence using Visual C++ and CUDD package, and undertake some experimental tests. It was shown that the OBDD scheme generated feasible assembly sequences correctly and completely.
Recommending scientific articles using citeulike
Authors: Toine Bogers, Antal van den Bosch
Venue: Proceedings of the 2008 ACM conference on Recommender systems (2008)

We describe the use of the social reference management website CiteULike for recommending scientific articles to users, based on their reference library. We test three different collaborative filtering algorithms, and find that user-based filtering performs best. A temporal analysis of the data indexed by CiteULike shows that it takes about two years for the cold-start problem to disappear and recommendation performance to improve.
Multi-ring Infrastructure for Content Addressable Networks
Authors: Djelloul Boukhelef, Hiroyuki Kitagawa
Venue: Proceedings of the OTM 2008 Confederated International Conferences, CoopIS, DOA, GADA, IS, and ODBASE 2008. Part I on On the Move to Meaningful Internet Systems: (2008)

We propose in this paper RCAN, a novel topology to improve the routing performance of CAN overlays while minimizing the maintenance overhead during frequent nodes join and departure in large size networks. The key idea for our design is to equip each node with a few long links towards some distant nodes in the systems. Long links are clockwise directed and wrap around to form small rings along each dimension (multi-ring). Unlike other protocols, RCAN does not assume a priori fixed limits for the network size or the routing state per node. The number of rings and their sizes self-adjust as nodes join and leave. Nodes auto-adapt their routing states to cope with network changes. RCAN is a pure P2P design, where all nodes assume the same responsibility. Following a uniform greedy routing, RCAN uses O(logn) routing state and achieves O(logn) routing performance which is asymptotically optimal. Besides, the communication cost of join operation is reduced to O(logn) messages, instead of O(log2 n) in other existing protocols, such as: Chord, pastry, SCAN, etc. Our secondary aim is also to enhance nodes' connectivity to provide more routing flexibility and robustness against failures. Through simulation we demonstrate the full scalability and efficiency of our design and its advantages over other existing methods.
A dynamically reconfigurable stereoscopic/panoramic vision mobile robot head controlled from a virtual environment
Authors: Walter A. Aprile, Emanuele Ruffaldi, Edoardo Sotgiu, Antonio Frisoli, Massimo Bergamasco
Venue: The Visual Computer: International Journal of Computer Graphics (2008)

We have built a mobile robotic platform that features an Active Robotic Head (ARH) with two high-resolution cameras that can be switched during robot operation between two configurations that produce respectively panoramic and stereoscopic images. Image disparity is used for improving the quality of the texture. The robot head switches dynamically, based on robot operation between the stereoscopic configuration and the panoramic configuration.
Breaking the silos: access and service convergence over the mobile internet
Authors: Victor C.M. Leung, Terrence Wong, Peyman TalebiFard
Venue: Proceedings of the 11th international symposium on Modeling, analysis and simulation of wireless and mobile systems (2008)

Conventional network services operate like silos in that a specific set of services are offered over a specific type of access network. As access networks evolve to provide IP-based packet access, it becomes attractive to break these "service silos" by offering a converged set of IP-based services to users who may access these services using a number of alternative access networks. This trend has started with 3rd generation cellular mobile networks, which have standardized on the use of the IP Multimedia Subsystem (IMS) to manage user access to a wide variety of multimedia services over the mobile Internet, while facilitating interworking of heterogeneous wireless and landline access networks. This paper reviews the function of the IMS, and presents the use of the Service Oriented Architecture (SOA) above IMS to further enable service convergence. Examples of converged services are presented. Technical challenges in network and service convergence are discussed and some recent results are presented.
Ubiquitous computing for remote cardiac patient monitoring: a survey
Authors: Sunil Kumar, Kashyap Kambhatla, Fei Hu, Mark Lifson, Yang Xiao
Venue: International Journal of Telemedicine and Applications (2008)

New wireless technologies, such as wireless LAN and sensor networks, for telecardiology purposes give new possibilities for monitoring vital parameters with wearable biomedical sensors, and give patients the freedom to be mobile and still be under continuous monitoring and thereby better quality of patient care. This paper will detail the architecture and quality-of-service (QoS) characteristics in integrated wireless telecardiology platforms. It will also discuss the current promising hardware/software platforms for wireless cardiac monitoring. The design methodology and challenges are provided for realistic implementation.
Efficient modulo 2n+1 adder architectures
Authors: H. T. Vergos, C. Efstathiou
Venue: Integration, the VLSI Journal (2009)

In this manuscript, we introduce novel carry lookahead (CLA) and parallel-prefix architectures for the design of modulo 2^n+1 adders with operands in the diminished-1 number representation. The proposed architectures are based on the use of Ling carries' computation units and they lead to faster and/or smaller adders than the already known ones that are based on the traditional carry signals.
Numerically satisfactory solutions of Kummer recurrence relations
Authors: Javier Segura, Nico M. Temme
Venue: Numerische Mathematik (2008)

Pairs of numerically satisfactory solutions as $${n \rightarrow \infty}$$for the three-term recurrence relations satisfied by the families of functions $${_1{\rm F}_1(a+\epsilon_1 n; b +\epsilon_2 n; z)}$$, $${\epsilon_i \in {\mathbb Z}}$$, are given. It is proved that minimal solutions always exist, except when $${\epsilon_2=0}$$and z is in the positive or negative real axis, and that $${_1{\rm F}_1 (a+ \epsilon_1 n; b +\epsilon_2 n; z)}$$is minimal as $${n \rightarrow + \infty}$$whenever $${\epsilon_2 > 0}$$. The minimal solution is identified for any recurrence direction, that is, for any integer values of $${\epsilon_1}$$and $${\epsilon_2}$$. When $${\epsilon_2 \neq 0}$$the confluent limit $${\lim_{b \rightarrow \infty}\,_1{\rm F}_1(\gamma b; b; z)= e^{\gamma z}}$$, with $${\gamma \in {\mathbb C}}$$fixed, is the main tool for identifying minimal solutions together with a connection formula; for $${\epsilon_2=0}$$, $${\lim_{a \rightarrow +\infty}\,_1{\rm F}_1(a; b; z)/_0{\rm F}_1(; b; az)=e^{z/2}}$$is the main tool to be considered.
Specifying and implementing privacy-preserving cryptographic protocols
Authors: Theodoros Balopoulos, Stefanos Gritzalis, Sokratis K. Katsikas
Venue: International Journal of Information Security (2008)

Formal methods are an important tool for designing secure cryptographic protocols. However, the existing work on formal methods does not cover privacy-preserving protocols as much as other types of protocols. Furthermore, privacy-related properties, such as unlinkability, are not always easy or even possible to prove statically, but need to be checked dynamically during the protocol&#x2019;s execution. In this paper, we demonstrate how, starting from an informal description of a privacy-preserving protocol in natural language, one may use a modified and extended version of the Typed MSR language to create a formal specification of this protocol, typed in a linkability-oriented type system, and then use this specification to reach an implementation of this protocol in Jif, in such a way that privacy vulnerabilities can be detected with a mixture of static and runtime checks.
A Mathematics Morphology Based Algorithm of Obstacles Clustering
Authors: Qiang Zhang
Venue: Proceedings of the 2008 International Conference on Computer Science and Software Engineering - Volume 01 (2008)

As a large amount of data stored in spatial databases, people may like to find groups of data which share similar features. Thus cluster analysis becomes an important area of research in data mining. In the real world, there exist many physical obstacles such as rivers, lakes and highways, and their presence may affect the result of clustering substantially. However, most of clustering algorithms can not deal with obstacles. In this paper, a new clustering algorithm MMO is proposed for the problem of clustering in the presence of obstacles. The main contributions are: two new mathematics morphological operators are introduced to discover clusters in the presence of obstacles. Our new operators are more accurate than the ordinary operators: open and close. The performance tests show that: MMO is effective in discovering clusters of arbitrary shape in the presence of obstacles; it is very efficient with a complexity of O(N+M) , where N is the number of data points, and M is the number of obstacles; it is not sensitive to noise.
Influence of material stiffness and geometrical variations on the electro-thermally driven microactuator performance
Authors: M. Shamshirsaz, M. Maroufi, M. B. Asgari, M. Gheisarieha
Venue: Microsystem Technologies (2008)

In order to make robust design of microdevices, it is important to implement a model considering uncertainty analysis. The high cost of experimentation and product development has led to an emphasis on simulated based design to achieve the success in the first-pass design and reliability. In this paper, finite element model is developed to investigate the effects of geometrical and material stiffness variations on an electro-thermally driven microactuator performance as an example. These microactuators are generally composed of two suspended beam (arm) joined at the free end. This device generates deflection through asymmetric heating of the hot and cold polysilicon arms with variable length or cross-section. These microactuators based on the force and deflection characteristic of elastic members are particularly sensitive to uncertainty in material properties. Polysilicon as a microdevice material shows a wide variation rang for Young&#x2019;s modulus from batch to batch fabrication process. Also, the microfabrication process that are utilized for microdevice production can yield sometimes shapes that are not geometrically perfect, either due to the microfabrication process limitations itself or because of phenomena that take place during or after microfabrication. These geometrical errors can decrease the net cross section and will affect both modeling and experimental results. The effect of fillet radius at the juncture of this flexible microactuator and contact pads is investigated in this model. The residual stresses due to the fabrication process are taken into account too. The analysis is performed at multiple input voltages to estimate uncertainty bands around the deflection curve of the microactuator. Simulation results are compared with experimental results in literature. The results demonstrate how each of these factors affects the microactuator performance and justifies the deviation of previous nominal results from experimental results.
Power management in the EPOS system
Authors: Geovani Ricardo Wiedenhoft, Lucas Francisco Wanner, Giovani Gracioli, Antônio Augusto Fröhlich
Venue: ACM SIGOPS Operating Systems Review (2008)

Power management strategies for embedded systems typically rely on static, application driven deactivation of components (e.g. sleep, suspend), or on dynamic voltage and frequency scaling. However, the design and implementation of these strategies in embedded operating system often fail to deal with real-time and quality-of-service (QoS) requirements. The EPOS system implements an infra-structure that supports both static (application-driven) and dynamic (system-driven) power management. In this work, this infrastructure is used to explore energy as a parameter for QoS in embedded systems, with the goal of guaranteeing energy consumption metrics, while preserving the deadlines of essential (hard real-time) tasks. Given a set of real-time tasks and their associated energy consumption, we provide equations to check schedulability in project-time. At runtime, a preemptive scheduler for imprecise tasks prevents the execution of optional subtasks whenever there is the possibility of deadline loss or depletion of the energy source. We show that this mechanism is effective in controlling energy consumption and ensuring "best-effort" computation without deadline loss.
Causal temporal constraint networks for representing temporal knowledge
Authors: Ángel Fernández-Leal, Vicente Moret-Bonillo, Eduardo Mosqueira-Rey
Venue: Expert Systems with Applications: An International Journal (2009)

In this work we describe causal temporal constraint networks (CTCN) as a new computable model for representing temporal information and efficiently handling causality. The proposed model enables qualitative and quantitative temporal constraints to be established, introduces the representation of causal constraints, and suggests mechanisms for representing inexact temporal knowledge. The temporal handling of information is achieved by structuring the information in different interpretation contexts, linked to each other through an inference mechanism which obtains interpretations that are consistent with the original temporal information. In carrying out inferences, we take into account the temporal relationships between events, the possible inexactitude associated with the events, and the atemporal or static information which affects the interpretation pattern being considered. The proposed schema is illustrated with an application developed using the CommonKADS methodology.
Experiences on Using TRAKLA2 to Teach Spatial Data Algorithms
Authors: Jussi Nikander, Juha Helminen, Ari Korhonen
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

This paper reports on the results of a two year project in which visual algorithm simulation exercises were developed for a spatial data algorithms course. The success of the project is studied from several point of views, i.e., from developer's, teachers's, and student's perspective. The amount of work, learning outcomes, and feasibility of the system has been estimated based on the data gathered during the project. The results are encouraging, which motivates to extend the concept also for other courses in the future.
Combining on-demand and opportunistic routing for intermittently connected networks
Authors: J. Boice, J. J. Garcia-Luna-Aceves, K. Obraczka
Venue: Ad Hoc Networks (2009)

While current on-demand routing protocols are optimized to take into account unique features of mobile ad-hoc networks (MANETs) such as frequent topology changes and limited battery life, they often do not consider the possibility of intermittent connectivity that may lead to arbitrarily long-lived partitions. In this work, we introduce the space-content-adaptive-time routing (SCaTR) framework, which enables data delivery in the face of both temporary and long-lived MANET connectivity disruptions. SCaTR takes advantage of past connectivity information to effectively route traffic towards destinations when no direct route from the source exists. We show through simulations that, when compared to traditional on-demand protocols, as well as opportunistic routing (e.g., epidemic), SCaTR increases delivery ratio with lower signaling overhead in a variety of intermittently connected network scenarios. We also show that SCaTR performs as well as on-demand routing in well-connected networks and in scenarios with no mobility predictability (e.g., random mobility). In the latter case, SCaTR delivers comparable reliability to epidemic routing with considerably lower overhead.
Watching television over an IP network
Authors: Meeyoung Cha, Pablo Rodriguez, Jon Crowcroft, Sue Moon, Xavier Amatriain
Venue: Proceedings of the 8th ACM SIGCOMM conference on Internet measurement (2008)

For half a century, television has been a dominant and pervasive mass media, driving many technological advances. Despite its widespread usage and importance to emerging applications, the ingrained TV viewing habits are not completely understood. This was primarily due to the difficulty of instrumenting monitoring devices at individual homes at a large scale. The recent boom of Internet TV (IPTV) has enabled us to monitor the user behavior and network usage of an entire network. Such analysis can provide a clearer picture of how people watch TV and how the underlying networks and systems can better adapt to future challenges. In this paper, we present the first analysis of IPTV workloads based on network traces from one of the world's largest IPTV systems. Our dataset captures the channel change activities of 250,000 households over a six month period. We characterize the properties of viewing sessions, channel popularity dynamics, geographical locality, and channel switching behaviors. We discuss implications of our findings on networks and systems, including the support needed for fast channel changes. Our data analysis of an operational IPTV system has important implications on not only existing and future IPTV systems, but also the design of the open Internet TV distribution systems such as Joost and BBC's iPlayer that distribute television on the wider Internet.
Adaptive linear minimum mean square error restoration: influence on hyperspectral detection strategy
Authors: Jean-Michel Gaucel, Mireille Guillaume, Salah Bourennane
Venue: International Journal of Remote Sensing (2008)

In this paper, we consider the problem of multichannel restoration. Current multichannel least squares restoration filters assume the separability of the signal covariance, which describes the between-channel and within-channel relationships. We propose a new solution for a multichannel restoration scheme, the Adaptive Linear Minimum Mean Square Error (ALMMSE), based on a local signal model, without the hypothesis of spectral and spatial separability. The proposed filter is developed to be used as a preprocessing step for detection in hyperspectral imagery. Tests on real data show that the proposed filter enables us to enhance detection performance in target detection and anomaly detection applications with the well-known hyperspectral imagery detection algorithms AMF and RX. The comparison with detection results, after classical restoration methods, shows the superiority of the proposed approach for hyperspectral images.