Distributed database systems use commit protocols to ensure atomicity in case of distributed transactions and a wide variety of commit protocols have been proposed so far. Two–phase commit (2PC) is a widely accepted standard protocol for... more
Distributed database systems use commit protocols to ensure atomicity in case of distributed transactions and a wide variety of commit protocols have been proposed so far. Two–phase commit (2PC) is a widely accepted standard protocol for distributed transactions. But 2PC suffer from blocking problem due to which three-phase commit (3PC) protocol was proposed which is an extension of 2PC. This paper present a review and comparison of commit protocols used for distributed database systems.
This paper provides a formal semantic analysis of classifiers in Hungarian. We focus on the puzzle posed by classifier optionality in Hungarian, where most nouns can co-occur with a classifier, but do not have to. Here we show that the... more
This paper provides a formal semantic analysis of classifiers in Hungarian. We focus on the puzzle posed by classifier optionality in Hungarian, where most nouns can co-occur with a classifier, but do not have to. Here we show that the presence or absence of classifiers in a numeral expression has semantic consequences. Evidence in support of our analysis comes from nouns that are polysemous and have a physical object and an informational object sense, such as konyv 'book', festm eny 'painting', magazin 'magazine'. We argue that Hungarian classifiers, such as darab, can take count nouns as their complement, and their role is restricting the domain of counting to physically distinct, Maximally Strongly Self-Connected entities (Grimm 2012) in the denotation of the noun they modify.
This paper argues that bare singular noun phrases in Brazilian Portuguese are mass nouns denoting kinds. We show that the prima facie arguments against treating bare singulars as mass nouns do not hold water, since they contrast atomic... more
This paper argues that bare singular noun phrases in Brazilian Portuguese are mass nouns denoting kinds. We show that the prima facie arguments against treating bare singulars as mass nouns do not hold water, since they contrast atomic bare singulars with substance mass nouns such as ouro ‘gold’, rather than with atomic mass nouns such as mobília ‘furniture’. We show that in fact bare singulars and atomic mass nouns show the same properties with respect to distributive predicates and reciprocals. We then show that in distribution and interpretation, bare singulars behave like mass nouns and not like bare plurals. We give an analysis of the semantics of bare singulars/mass nouns in the framework of Rothstein (2010), treating them as kind denoting terms, while proposing that bare plurals are generated as plural predicates NPs, as proposed by Krifka (2004), and show how this explains the differences in distribution and interpretation. We conclude that bare singulars can be the complements of mass quantifiers such as muito ‘much’ and quanto ‘how much’, in which case these behave semantically exactly like mass nouns: quanto livro with the bare singular asks about the overall measurements of a quantity of books in terms of volume or weight and is thus an expression of measure, while quantos livros with the plural count noun asks only for the cardinality of the set of books under discussion and thus is a question about counting.► Bare singular NPs in Brazilian Portuguese are like mass nouns in distribution and interpretation. ► Bare singular and mass NPs differ from bare plurals. ► Bare singular and mass NPs are lexical items denoting kinds, bare plurals are count predicates. ► An account of the above is given, based on Rothstein 2010's theory of the count/mass distinction ► Bare singulars occur with mass quantifiers, supporting this account.
ABSTRACT The increase in the popularity of agents and transactions has made it necessary to develop a framework for multi-agent interaction. Traditional database transactions, which use the ACID (atomicity, consistency, isolation,... more
ABSTRACT The increase in the popularity of agents and transactions has made it necessary to develop a framework for multi-agent interaction. Traditional database transactions, which use the ACID (atomicity, consistency, isolation, durability) properties, must be extended to meet the needs present in an agent-based peer-to-peer environment. By encapsulating our agents and having them conform to new commitment rules, transactions can be carried out safely and effectively
Transaction support is crucial in mobile data management. Specific characteristics of mobile environments (e.g. variable bandwidth, disconnections, limited resources on mobile hosts) make traditional transaction management techniques no... more
Transaction support is crucial in mobile data management. Specific characteristics of mobile environments (e.g. variable bandwidth, disconnections, limited resources on mobile hosts) make traditional transaction management techniques no longer appropriate. Several models for mobile transactions have been proposed but it is difficult to have an overview of all of them. This paper analyzes and compares several contributions to mobile transactions. The analysis distinguishes two groups of models. The first group includes proposals where transactions are completely or partially executed on mobile hosts. In this group we focus on ACID properties support. The second group considers transactions requested by mobile hosts and executed on the wired network. In this case, ACID properties are not compromised and focus is on supporting mobile host movements during transaction execution. Discussions pointing out limitations, interesting solutions and research perspectives complete this paper.
This paper presents SOAR: the first oblivious atomicity assertion with polynomial complexity. SOAR enables to check atomicity of a single-writer multi-reader register implementation. The basic idea underlying the low overhead induced by... more
This paper presents SOAR: the first oblivious atomicity assertion with polynomial complexity. SOAR enables to check atomicity of a single-writer multi-reader register implementation. The basic idea underlying the low overhead induced by SOAR lies in greedily checking, in a backward manner, specific points of an execution where register operations could be linearized, rather than exploring all possible precedence relations among these. We illustrate the use of SOAR by implementing it in +CAL. The performance of the resulting automatic verification outperforms comparable approaches by more than an order of magnitude already in executions with only 6 read/write operations. This difference increases to 3-4 orders of magnitude in the “negative” scenario, i.e., when checking some non-atomic execution, with only 5 operations. For example, checking atomicity of every possible execution of a single-writer single-reader (SWSR) register with at most 2 write and 3 read operations with the state of the art oblivious assertion takes more than 58 hours to complete, whereas SOAR takes just 9 seconds.
This paper proposes two approaches to managing concurrency in Java using a guarded region abstraction. Both approaches use revocation of such regions – the ability to undo their effects automatically and transparently. These new... more
This paper proposes two approaches to managing concurrency in Java using a guarded region abstraction. Both approaches use revocation of such regions – the ability to undo their effects automatically and transparently. These new techniques alleviate many of the constraints that inhibit construction of transparently scalable and robust concurrent applications. The first solution, revocable monitors, augments existing mutual exclusion monitors with the ability to resolve priority inversion and deadlock dynamically, by reverting program execution to a consistent state when such situations are detected, while preserving Java semantics. The second technique, transactional monitors, extends the functionality of revocable monitors by implementing guarded regions as lightweight transactions that can be executed concurrently (or in parallel on multiprocessor platforms). The presentation includes discussion of design and implementation issues for both schemes, as well as a detailed performanc...
Abstract. In this paper, we propose a efficient and secure point mul-tiplication algorithm, based on double-base chains. This is achieved by taking advantage of the sparseness and the ternary nature of the so-called double-base number... more
Abstract. In this paper, we propose a efficient and secure point mul-tiplication algorithm, based on double-base chains. This is achieved by taking advantage of the sparseness and the ternary nature of the so-called double-base number system (DBNS). The speed-ups are the re- ...
In this paper we address the problem of protecting elliptic curve scalar multiplication implementations against side-channel analysis by using the atomicity principle. First of all we reexamine classical assumptions made by scalar... more
In this paper we address the problem of protecting elliptic curve scalar multiplication implementations against side-channel analysis by using the atomicity principle. First of all we reexamine classical assumptions made by scalar multiplication designers and we point out that some of them are not relevant in the context of embedded devices. We then describe the state-of-the-art of atomic scalar multiplication and propose an atomic pattern improvement method. Compared to the most ef?cient atomic scalar multiplication published so far, our technique shows an average improvement of up to 10.6%.
Traditionally, the transaction paradigm is defined by the ACID properties (Atomicity, Consistency, Isolation and Durability) which implementation is based on mechanisms such as commitment and concurrency control protocols. This paper, our... more
Traditionally, the transaction paradigm is defined by the ACID properties (Atomicity, Consistency, Isolation and Durability) which implementation is based on mechanisms such as commitment and concurrency control protocols. This paper, our mainly focuses on a context-aware adaptation for the transaction management. We therefore propose an adaptable transaction model (AdapT) and a commit protocol (aTCP:Adaptable Transaction Commit Protocol) which allows for adaptation to the applications requirements and mobile context in terms of transaction properties and execution cost. We also propose a policy-based context-aware architecture for the implementation.
Widespread availability of IP multicast has renewed interest in structuring distributed applications around a group communication paradigm that exploits network-layer support for multicast applications. In the past, distributed systems... more
Widespread availability of IP multicast has renewed interest in structuring distributed applications around a group communication paradigm that exploits network-layer support for multicast applications. In the past, distributed systems that provided group communication supported a restricted group communication model. Such systems are either designed to provide reliable delivery with support for atomicity and causality or to provide simple unreliable, unordered multicast delivery. We believe that the group communication abstraction is useful to many application domains. However, the group communication requirements of an application vary widely from domain to domain. The paper describes a group communication toolkit called Clique that contains the basic building blocks required to provide a flexible group communication paradigm. Clique achieves support for a wide variety of applications by tailoring the underlying multicast mechanism to meet the application's group communicatio...
In this paper, we present a system of verbal and nominal classification based on atomic features which qualify wholes and parts of event and object denotations. The system proves to be motivated on both conceptual and empirical grounds.... more
In this paper, we present a system of verbal and nominal classification based on atomic features which qualify wholes and parts of event and object denotations. The system proves to be motivated on both conceptual and empirical grounds. Conceptually, it provides a ...
The paper proves by assertional means the correctness of a construction of Haldar and Subramanian of an atomic shared variable for one writer and one reader. This construction uses four unsafe variables and four safe boolean variables.... more
The paper proves by assertional means the correctness of a construction of Haldar and Subramanian of an atomic shared variable for one writer and one reader. This construction uses four unsafe variables and four safe boolean variables. Assignment to a safe but nonatomic variable is modelled as a repetition of random assignments concluded by an actual assignment. The proof obligation consists of four invariants. These are proved using 25 auxiliary invariants. The proof has been constructed and verified with the theorem prover NQTHM.
This paper presents a deterministic self-stabilizing algorithm that approximates a minimum vertex cover in anonymous networks with ratio 2 using the distributed scheduler and the link-register model with composite atomicity. No algorithm... more
This paper presents a deterministic self-stabilizing algorithm that approximates a minimum vertex cover in anonymous networks with ratio 2 using the distributed scheduler and the link-register model with composite atomicity. No algorithm with a better approximation ratio can exist. The algorithm stabilizes in O( min {n, Δ2, Δ log 3 n}) rounds and requires O(Δ) memory per node.
This paper argues that bare singular noun phrases in Brazilian Portuguese are mass nouns denoting kinds. We show that the prima facie arguments against treating bare singulars as mass nouns do not hold water, since they contrast atomic... more
This paper argues that bare singular noun phrases in Brazilian Portuguese are mass nouns denoting kinds. We show that the prima facie arguments against treating bare singulars as mass nouns do not hold water, since they contrast atomic bare singulars with substance mass nouns such as ouro ‘gold’, rather than with atomic mass nouns such as mobília ‘furniture’. We show
Consistency maintenance is an important issue in groupware systems. This article proposes an exclusive version locking scheme for consistency maintenance in Internet-based real-time collaborative editing environments. With this scheme, it... more
Consistency maintenance is an important issue in groupware systems. This article proposes an exclusive version locking scheme for consistency maintenance in Internet-based real-time collaborative editing environments. With this scheme, it is not necessary to propagate lock requests over the network. Locks will be automatically enforced by the system in a distributed way. The scheme supports concurrent editing on the same object by multi-versioning. Individual users’ concurrent conflicting intentions are thus accommodated in different versions. Meanwhile, each version is guaranteed to be exclusively locked by one user such that conflict resolution processes among users can be facilitated. Several version locking protocols are also defined to preserve the atomicity of a user's multiple intentions on the same object. The scheme and protocols have been implemented in a research prototype called POLO.
