Union-find Research Articles

Union commitment and participation: a 10-year longitudinal study.

The authors longitudinally investigated the causal nature of the relationship between union commitment and participation in informal union activities. A total of 134 members of the National Association of Letter Carriers were studied over a 10-year period. Using cross-lagged regression analysis, early union commitment was found to predict the level of informal union participation 10 years later. The reverse and reciprocal relationships were not supported. These findings support and extend earlier research on the causal nature of the short-term relationship between union commitment and participation. The implications of the findings for researchers and labor unions are discussed.

Scalable hierarchical locking for distributed systems

Middleware components are becoming increasingly important as applications share computational resources in distributed environments, such as high-end clusters with ever larger number of processors, computational grids and increasingly large server farms. One of the main challenges in such environments is to achieve scalability of synchronization. In general, concurrency services arbitrate resource requests in distributed systems. But concurrency protocols currently lack scalability. Adding such guarantees enables resource sharing and computing with distributed objects in systems with a large number of nodes. The objective of our work is to enhance middleware services to provide scalability of synchronization and to support state replication in distributed systems. We have designed and implemented a middleware protocol in support of these objectives. Its essence is a peer-to-peer protocol for multi-mode hierarchical locking, which is applicable to transaction-style processing and distributed agreement. We demonstrate high scalability combined with low response times in high-performance cluster environments. Our technical contribution is a novel, fully decentralized, hierarchical locking protocol to enhance concurrency in distributed resource allocation following the specification of general concurrency services for large-scale data and object repositories. Our experiments on an IBM SP show that the number of messages approaches an asymptote at 15 node from which point on the message overhead is in the order of 3–9 messages per request, depending on system parameters. At the same time, response times increase linearly with a proportional increase in requests and, consequently, higher concurrency levels. Specifically, in the range of up to 80 nodes, response times under 10 ms are observed for critical sections that are one 25th the size of non-critical code. The high degree of scalability and responsiveness of our protocol is due in large to a high level of concurrency upon resolving requests combined with dynamic path compression for request propagation paths. Our approach is not only applicable to CORBA, its principles are shown to provide benefits to general distributed concurrency services and transaction models. Besides its technical strengths, our approach is intriguing due to its simplicity and its wide applicability, ranging from large-scale clusters to server-style computing.

Between the State and Labour: The Conflict of Chinese Trade Unions' Double Identity in Market Reform

Chinese official union's reactions to labour contentions can be explained by its double institutional identity as both a state apparatus and the labour organization. Before the reform, the union did not confront tense conflicts between its double identity, as its representation function was absorbed by the paternalist state. As the state retreats from socialist paternalism, the union finds that its double identity becomes contradictory. What role the union is apt to play in any particular dispute issue is determined by whether and to what extent its double institutional identity is in conflict. Specifically, three patterns of the union's roles can be identified: representing, mediating and pre-empting. State corporatism remains the fundamental institutional parameter that shapes the union's behaviour. A combination of state corporatism binding the union and rampant capitalist assaults on workers tends either to produce more spontaneous protests or to force workers to seek independent organizing outside the ACFTU framework.

IP 주소 검색의 속도 향상을 위한 분할된 압축 트라이 구조

Packet processing speed of routers as well as transmission speed of physical links gives a great effect on IP packet transfer rate in Internet. The router forwards a packet after determining the next hop to the packet`s destination. IP address lookup is a main design issue for high performance routers. In this paper, we propose a partitioned compressed-trie for speeding-up IP address lookup algorithms based on tie data structure by exploiting path compression. In the ,proposed scheme, IP prefixes are divided into several compressed-tries and lookup is performed on only one partitioned compressed-trie. Memory access time for IP address lookup is lessen due to compression technique and memory required for maintaining partition does not increased.

Efficient hardware architecture for fast IP address lookup

A multi-gigabit internet protocol (IP) router may receive several million packets per second from each input link. For each packet, the router needs to find the longest matching prefix in the forwarding table in order to determine the packet's next-hop. An efficient hardware solution for the IP address lookup problem is presented. The problem is modelled as a searching problem on a binary-trie. The binary-trie is partitioned into fixed size non-overlapping subtrees. Each subtree is represented using a bit-vector and can be searched in parallel for the best matching prefix in a few nanoseconds. The address lookup is implemented using a hardware pipeline with a throughput of one lookup per memory access. A distinguishing feature of the design is that forwarding table entries are not replicated in the data structure. Hence, table updates can be done in constant time with only a few memory accesses. The approach can be extended to IPv6. By applying path compression, the amount of memory required is upper bounded by O(N) where N is the number of prefixes in the routing table.

The Safe-Harbor Agreement Between the United States and Europe: A Missed Opportunity to Balance the Interests of E-Commerce and Privacy Online?

This analysis of the "safe harbor" agreement between the United States and the European Union finds that US. corporations that abided by its provisions afforded more privacy protection to Europeans than Americans under U.S. law. It seemed that the agreement might prompt the U.S. to shift its privacy policy in accordance with the European tradition, which views personal privacy as a "human" right. However, the authors conclude that the failure to enact more comprehensive online privacy legislation in the U.S. can be attributed to the continuing characterization of personal data privacy as a matter of "consumer" rights rather than civil rights.

경로 압축을 이용한 DJ 그래프의 지연 감축 알고리즘

효과적이고 정확한 데이터 흐름 문제 분석은 흐름그래프와 지배자 트리 그리고 DJ 그래프를 사용한다. 데이터 흐름 문제 해결은 흐름 그래프를 안전하게 지배자 트리로 감축하는 것이다. 흐름 그래프는 파스 트리를 대신하고, DJ 그래프는 감축 가능하거나 감축이 불가능한 흐름 그래프를 지배자 트리로 정확하게 감축하는데 이용된다. 본 연구에서는 Tarjan의 경로 압축 알고리즘을 이용하기 위하여 Top 노드 찾기 알고리즘을 제시하고 기존의 지연감축 알고리즘을 경로압축을 이용하여 개선한다. 경로압축을 이용한 지연감축 알고리즘은 DJ 그래프를 지연 감축하면서 노드를 끌어올려 지배자 트리의 경로를 압축시킨다. 실제로 제안된 알고리즘은 22% 정도 노드들을 끌어올렸고, 20% 정도 경로를 압축시켰다. 압축된 지배자 트리는 효과적인 데이터 흐름 분석을 가능하게 하고, 코드 최적화 과정의 노드 끌어올리기 효과를 가져와 코드 최적화 과정의 복잡도를 개선하는 효과를 가져온다. The effective and accurate data flow problem analysis uses the dominator tree and DJ graphs. The data flow problem solving is to safely reduce the flow graph to the dominator tree. The flow graph replaces a parse tree and used to accurately reduce either reducible or irreducible flow graph to the dominator tree. In this paper, in order to utilize Tarian's path compress algorithm, the Top node finding algorithm is suggested and the existing delay reduction algorithm is improved using Path compression. The delayed reduction a1gorithm using path compression actually compresses the pathway of the dominator tree by hoisting the node while reducing to delay the DJ graph. Realty, the suggested algorithm had hoisted nodes in 22% and had compressed path in 20%. The compressed dominator tree makes it possible to analyze the effective data flow analysis and brings the improved effect for the complexity of code optimization process with the node hoisting effect of code optimization process.

Finding connected components in digital images by aggressive reuse of labels

Abstract An efficient algorithm is presented to label the connected components in array representation of very huge 2-D images that one works with in remote sensing applications. A new data structure is suggested to maintain the equivalence table that makes use of a modified version of Union-Find algorithms. The operations supported by the equivalence table enable aggressive reuse of labels and bound the size of the table by ⌊N/2⌋+1 , for a N × N image. It is also shown that the maintenance of the table has an overall linear amortized cost.

An Experimental Study of Compression Methods for Dynamic Tries

We study an order-preserving general purpose data structure for binary data, the LPC-trie. The structure is a compressed trie, using both level and path compression. The memory usage is similar to that of a balanced binary search tree, but the expected average depth is smaller. The LPC-trie is well suited to modem language environments with efficient memory allocation and garbage collection. We present an implementation in the Java programming language and show that the structure compares favorably with a balanced binary search tree.

A comparison of algorithms for connected set openings and closings

The implementation of morphological connected set operators for image filtering and pattern recognition is discussed. Two earlier algorithms based on priority queues and hierarchical queues, respectively, are compared to a more recent union-find approach. Unlike the earlier algorithms which process regional extrema in the image sequentially, the union-find method allows simultaneous processing of extrema. In the context of area openings, closings, and pattern spectra, the union-find algorithm outperforms the previous methods on almost all natural and synthetic images tested. Finally, extensions to pattern spectra and the more general class of attribute operators are presented for all three algorithms, and memory usages are compared.

A auditoria legal na União Europeia: enquadramento, debate actual e perspectivas futuras

A auditoria legal na União Europeia, encontra-se, presentemente, numa grande encruzilhada. Imposta pelos poderes públicos e pelas directivas comunitárias, é criticada pelos empresários por não acrescentar valor ao negócio, e, duma maneira geral, pela sociedade que ao atribuir-lhe a característica de bem público, esperava dela respostas mais amplas do que aquelas que os auditores, espartilhados por um quadro normativo e jurídico-técnico construído pelas suas associações profissionais, conseguem ou querem facultar ao público em geral. Com efeito, as normas de auditoria que tratam do planeamento, execução e avaliação do trabalho do auditor, têm sido o refúgio eleito pelos auditores e uma justificação esgrimida, unanimemente, pela classe, para recusar liminarmente o alargamento das funções de auditoria à análise da viabilidade da empresa e à detecção de erros e fraudes. Neste contexto, a função de auditoria legal está sendo, na actualidade, fortemente criticada por não proporcionar ao público "certezas" de que: as declarações financeiras estão correctas, a empresa não falirá, não houve fraudes ou irregularidades, a empresa agiu dentro da lei, foi administrada de forma competente e adoptou uma atitude responsável face aos assuntos ambientais e sociais. É, pois, o objectivo deste trabalho, apresentar em relação à União Europeia, a origem da auditoria legal, e, em termos mais gerais, as inquietações do presente e perspectivar a função, num futuro não muito distante.

A Generalization of a Lower Bound Technique due to Fredman and Saks

{In a seminal paper of 1989, Fredman and Saks proved lower bounds for some important data-structure problems in the cell probe model. In particular, lower bounds were established on worst-case and amortized operation cost for the union-find problem and the prefix sum problem. The goal of this paper is to turn their proof technique into a general tool that can be applied to different problems and computational models. To this end we define two quantities: Output Variability depends only on the model of computation. It indicates how much variation can be found in the results of a program with certain resource bounds. This measures in some sense the power of a model. Problem Variability characterizes in a similar sense the difficulty of the problem.

Efficiently computing and updating triangle strips for real-time rendering

Triangle strips are a widely used hardware-supported data-structure to compactly represent and efficiently render polygonal meshes. In this paper we survey the efficient generation of triangle strips as well as their variants. We present efficient algorithms for partitioning polygonal meshes into triangle strips. Triangle strips have traditionally used a buffer size of two vertices. In this paper we also study the impact of larger buffer sizes and various queuing disciplines on the effectiveness of triangle strips. View-dependent simplification has emerged as a powerful tool for graphics acceleration in visualization of complex environments. However, in a view-dependent framework the triangle mesh connectivity changes at every frame making it difficult to use triangle strips. In this paper we present a novel data-structure, Skip Strip, that efficiently maintains triangle strips during such view-dependent changes. A Skip Strip stores the vertex hierarchy nodes in a skip-list-like manner with path compression. We anticipate that Skip Strips will provide a road-map to combine rendering acceleration techniques for static datasets, typical of retained-mode graphics applications, with those for dynamic datasets found in immediate-mode applications.

A potential-based amortized analysis of the union-find data structure

We present a simple, new potential-based amortized analysis for the standard union-find data structure.

Lessons for the Australian Trade Union Movement from the Industrial Relations Policy Experiences of Britain and New Zealand

Abstract This paper draws on the industrial relations experiences of Britain and New Zealand in periods when economic rationalism held the ascendancy in their national policy agendas. In so doing, it looks at the impact of deregulatory provisions contained in laws directed at controlling the organisation and activities of trade unions. The paper finds that legislative reforms aimed at controlling the behaviour of trade unions are less effective in industrial relations environments characterised by a history of voluntarism and strong trade union presence in the workplace; and conversely, that reforming legislation aimed at achieving these ends is likely to be more effective in environments marked by a history of strong state support for compulsory arbitration and where trade unions are organisationally weak in the workplace. In view of the ‘Second Wave’ industrial relations legislation currently being considered by the Howard Government, the implication of these findings for Australian trade unions suggests that they must improve existing levels of workplace organisation if they are to avoid the fate of their New Zealand counterparts.

THE IMPACT OF INDUSTRIAL RELATIONS CLIMATE, ORGANIZATIONALCOMMITMENT, AND UNION LOYALTY ON ORGANIZATIONAL PERFORMANCE: A LONGITUDINAL STUDY.

This paper utilizes the theoretical framework of Gordon and Ladd (1990) to examine the relationship between industrial relations climate, organizational commitment and union loyalty and bank branch performance. Specifically, we investigate the factors that influence the development of a co-operative industrial relations climate, the impact of that climate on both organizational commitment and union loyalty, and how these and other variables (i.e., demographic, job related, organizational, union related, environmental and technological) affect branch level productivity, quality of service, absenteeism, and customer attrition. This research is undertaken in a large Australian based multinational banking organization. The data are drawn from 460 bank branches of unionized non-managerial employees across three time periods. The LISREL results indicate that a cooperative industrial relations climate was associated with significantly higher productivity and significantly lower absenteeism. In addition, both organizational commitment and union loyalty had positive impacts on productivity, with union loyalty also having a negative impact on absenteeism. Other explanatory variables that had significant total causal effects on productivity were job opportunity, union instrumentality (intrinsic), job satisfaction, procedural justice, union satisfaction, collectivist work orientation, gender (%female), openness, branch size, and branch transfer. Furthermore, we found that union instrumentality (intrinsic), collectivist work orientation, union satisfaction, and job opportunity had significant total effects on absenteeism. Finally, branch size displayed a direct negative effect on quality, while ATM transactions had a direct positive impact on customer attrition. The theoretical and practical implications of these findings for unions and organizations are discussed.

An n log n Algorithm for Online BDD Refinement

Binary decision diagrams are in widespread use in verification systems for the canonical representation of finite functions. Here we consider multivalued BDDs, which represent functions of the form ϕ: Bν→L, where L is a finite set of leaves. We study a rather natural online BDD refinement problem: a partition of the leaves of several shared BDDs is gradually refined, and the equivalence of the BDDs under the current partition must be maintained in a discriminator table. We show that it can be solved in O(nlogn) time if n bounds both the size of the BDDs and the total size of update operations. Our algorithm is based on an understanding of BDDs as the fixed points of an operator that in each step splits and gathers nodes. We apply our algorithm to show that automata BDD-represented transition functions can be minimized in time O(n·logn), where n is the total number of BDD nodes representing the automaton. This result is not an instance of Hopcroft's classical minimization algorithm, which breaks down for BDD-represented automata because of the BDD path compression property.

Efficient union-find for planar graphs and other sparse graph classes

We solve the Union-Find Problem (UF) efficiently for the case the input is restricted to several graph classes, namely partial k-trees for any fixed k, d-dimensional grids for any fixed dimension d and for planar graphs. The result on grids allows us to perform region growing techniques that are used for image segmentation in linear time. For planar graphs we develop a technique of decomposing such a graph into small subgraphs, patching, that might be useful for other algorithmic problems on planar graphs, too. By efficiency we do not only mean linear time in a theoretical setting but also a practical reorganization of memory such that a dynamic data structures for UF is allocated consecutively.

Linearity and Unprovability of Set Union Problem Strategies

In this paper we prove that strong postorder path compression systems have linear growth.

Distributed Fault Simulation Algorithms on Parallel Virtual Machine

In this paper, we describe distributed algorithms for combinational fault simulation assuming the classical stuck‐at fault model. Our algorithms have been implemented on a network of Sun workstations under the Parallel Virtual Machine (PVM) environment. Two techniques are used for subdividing work among processors – test set partition and fault set partition. The sequential algorithm for fault simulation, used on individual nodes of the network, is based on a novel path compression technique proposed in this paper. We describe experimental results on a number of ISCAS′85 benchmark circuits.