Results 11  20
of
67
Using a Large Linguistic Ontology for Internetbased Retrieval of ObjectOriented Components
 In Proceedings of 1997 Conference on Software Engineering and Knowledge Engineering. Madrid, Knowledge Systems Institute
, 1997
"... this paper adopts a language of limited expressiveness, privileging the simplicity of use as the most important requirement. We adopt a very simple graph structure for representing both queries and component data, but  differently from most of current systems  we do not assume the user to have f ..."
Abstract

Cited by 14 (1 self)
 Add to MetaCart
this paper adopts a language of limited expressiveness, privileging the simplicity of use as the most important requirement. We adopt a very simple graph structure for representing both queries and component data, but  differently from most of current systems  we do not assume the user to have familiarity with the vocabulary used for component encoding, relying on a large linguistic ontology like Sensus [Swartout et al. 1996] to perform the match between queries and data. In the encoding phase (which we assume to be a manual process supported by an interactive environment), a software analyst describes a component by a simple graph where nodes and arcs are labelled with English words. Since binary relations are not usually denoted by nouns, a special semantics is adopted for this graph, which is called Lexical Semantic Graph. English nouns appearing in the graph are recognized by a lexical interface based on Wordnet [Miller 1995], which asks the analyst to choose among possibly different senses associated to each word. The graph of words is therefore translated into a graph of senses, each one corresponding to a node in the Sensus ontology. The query graph is built by the user in a similar way, but the words chosen and the corresponding senses can be of course different, as well as the structure of the graph. Conceptually, the search process implements a graph matching algorithm, returning the identifiers of all components whose description is subsumed by the query. In the following section, we describe the main design choices of a project on software retrieval currently going on at Corinto 1 , a research consortium established to study and promote objectoriented technology. In section 3 we present the encoding and retrieval process in some detail, with the help of...
On the Complexity of Entailment in Propositional Multivalued Logics
, 1997
"... Multivalued logics have a long tradition in the philosophy and logic literature that originates from the work by / Lukaszewicz in the 20's. More recently, many AI researchers have been interested in this topic for both semantic and computational reasons. Multivalued logics have indeed been frequentl ..."
Abstract

Cited by 11 (0 self)
 Add to MetaCart
Multivalued logics have a long tradition in the philosophy and logic literature that originates from the work by / Lukaszewicz in the 20's. More recently, many AI researchers have been interested in this topic for both semantic and computational reasons. Multivalued logics have indeed been frequently used both for their semantic properties and as tools for designing tractable reasoning systems. We focus here on the computational aspects of multivalued logics. The main result of this paper is a detailed picture of the impact that the semantic definition, the syntactic form and the assumptions on the relative sizes of the inputs have on the complexity of entailment checking. In particular we show new polynomial cases and generalize polynomial cases already known in the literature for various popular multivalued logics. Such polynomial cases are obtained by means of two simple algorithms, sharing a common method. Dipartimento di Informatica e Sistemistica, Universit`a di Roma "La Sapien...
Compact DAG Representation and its Dynamic Scheduling
 JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING
, 1999
"... Scheduling large task graphs is an important issue in parallel computing. In this paper we tackle the two following problems : (1) how to schedule a task graph, when it is too large to t into memory? (2) How to build a generic program such that parameter values of a task graph can be given at runti ..."
Abstract

Cited by 11 (2 self)
 Add to MetaCart
Scheduling large task graphs is an important issue in parallel computing. In this paper we tackle the two following problems : (1) how to schedule a task graph, when it is too large to t into memory? (2) How to build a generic program such that parameter values of a task graph can be given at runtime? Our answers feature the parameterized task graph (PTG), which is a symbolic representation of the task graph. We propose a dynamic scheduling algorithm which takes a PTG as an entry and allows to generate a generic program. We present a theoritical study which shows that our algorithm nds good schedules for coarse grain task graphs, has a very low memory cost and a low computational complexity. When the average number of operations of each task is large enough, we prove that the scheduling overhead is negligible with respect to the makespan. We also provide experimental results that demonstrate the feasibility of our approach using several computeintensive kernels found in numerical s...
An ObjectOriented Framework For File Systems
 PH.D. THESIS IN PREPARATION, UNIVERSITY OF ILLINOIS AT URBANACHAMPAIGN
, 1992
"... ..."
NearCritical Path Analysis of Program Activity Graphs
, 1994
"... Program activity graphs can be constructed from timestamped traces of appropriate execution events. Information about the activities on the k longest execution paths is useful in the analysis of parallel program performance. In this paper, four algorithms for finding the nearcritical paths of prog ..."
Abstract

Cited by 7 (3 self)
 Add to MetaCart
Program activity graphs can be constructed from timestamped traces of appropriate execution events. Information about the activities on the k longest execution paths is useful in the analysis of parallel program performance. In this paper, four algorithms for finding the nearcritical paths of program activity graphs are presented and compared, including an efficient new algorithm that utilizes slack values calculated by the critical path method to perform a bestfirst search in linear space. The worstcase time and memory requirements of the new algorithm are in O(ke) and O(k+e), where e is the number of edges in the graph. Results confirming the efficiency of the algorithm are presented for five application programs. A framework for utilizing the nearcritical path information is also described. The framework includes both statistical summaries and visualization capabilities. Index TermsCritical path, program activity graph, instrumentation, parallel program performance analy...
Succinct representation of static packet classifiers
, 2006
"... We develop algorithms for the compact representation of the 2dimensional tries that are used for Internet packet classification. Our compact representations are experimentally compared with competing compact representations for multidimensional packet classifiers and found to simultaneously reduce ..."
Abstract

Cited by 6 (5 self)
 Add to MetaCart
We develop algorithms for the compact representation of the 2dimensional tries that are used for Internet packet classification. Our compact representations are experimentally compared with competing compact representations for multidimensional packet classifiers and found to simultaneously reduce the number of memory accesses required for a lookup as well as the memory required to store the classifier. 1
Engineering 'Unbounded' Reusable Ada Generics
 Proceedings of the Tenth National Conference on Ada Technology, ANCOST, Inc
, 1992
"... Most current programming languages (including Ada) provide some means of allowing the programmer to dynamically allocate and deallocate heap storage. This permits construction of “unbounded ” abstract data types, e.g., stacks, queues, oneway lists, etc. Unfortunately, the addition of dynamically al ..."
Abstract

Cited by 4 (1 self)
 Add to MetaCart
Most current programming languages (including Ada) provide some means of allowing the programmer to dynamically allocate and deallocate heap storage. This permits construction of “unbounded ” abstract data types, e.g., stacks, queues, oneway lists, etc. Unfortunately, the addition of dynamically allocated storage to the implementation of abstract data types is a complicated business. Unless special care is taken, it can lead to problems of storage leaks, dangling references, unwanted aliasing, and unexpected lengthy execution times (due to storage allocation and reclamation), among others. We propose a specific discipline for avoiding these problems. 1.
Vertex Splitting in Dags and Applications to Partial Scan Designs and Lossy Circuits
, 1990
"... Directed acyclic graphs (dags) are often used to model circuits. Path lengths in such dags represent circuit delays. In the vertex splitting problem, the objective is to determine a minimum number of vertices to split so that the resulting dag has no path of length d. This problem has application to ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
Directed acyclic graphs (dags) are often used to model circuits. Path lengths in such dags represent circuit delays. In the vertex splitting problem, the objective is to determine a minimum number of vertices to split so that the resulting dag has no path of length d. This problem has application to the placement of flipflops in partial scan designs, placement of latches in pipelined circuits, placement of signal boosters in lossy circuits and networks, etc. Several simplified versions of this problem are shown to be NPhard. A linear time algorithm is obtained for the case when the dag is a tree. A backtracking algorithm and heuristics are developed for general dags and experimental results using dags obtained from ISCAS benchmark circuits are obtained.
Design of Hyper States for ReducedState Sequence Estimation
 In Proceedings of the International Conference on Communications (ICC'95
"... A new method for the design of hyper states for reducedstate sequence estimation of trellis coded signals is proposed. Examples are given for trellis coded modulation (TCM) over channels with intersymbol interference (ISI). The complexity of the super trellis resulting from the combination of the ..."
Abstract

Cited by 3 (1 self)
 Add to MetaCart
A new method for the design of hyper states for reducedstate sequence estimation of trellis coded signals is proposed. Examples are given for trellis coded modulation (TCM) over channels with intersymbol interference (ISI). The complexity of the super trellis resulting from the combination of the TCM and ISI trellises is reduced by an algorithm that applies set partitioning principles to the set of super states. The method often allows to achieve asymptotic optimality at a low level of complexity. Simulations and comparisons with other methods show the superior performance of the proposed class of reducedstate sequence estimators (RSSE).
Multicast ATM Switches Based on Input Cells Scheduling
, 1999
"... this paper, we propose a prescheduling mechanism to precede the multicast switch. This mechanism will completely eliminate the problems mentioned above. Two architectures are designed to implement this mechanism. Analysis and simulations show that our design performs quite well. ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
this paper, we propose a prescheduling mechanism to precede the multicast switch. This mechanism will completely eliminate the problems mentioned above. Two architectures are designed to implement this mechanism. Analysis and simulations show that our design performs quite well.