scholarly journals Deriving session and union types for objects

2013 ◽  
Vol 23 (6) ◽  
pp. 1163-1219
Author(s):  
LORENZO BETTINI ◽  
SARA CAPECCHI ◽  
MARIANGIOLA DEZANI-CIANCAGLINI ◽  
ELENA GIACHINO ◽  
BETTI VENNERI
Keyword(s):  
Large Scale ◽  
Type System ◽  
Object Oriented Programming ◽  
Type Safety ◽  
Network Applications ◽  
Session Types ◽  
Safety Property ◽  
Core Language ◽  
Structured Communication ◽  
Full Proof

Guaranteeing that the parties of a network application respect a given protocol is a crucial issue.Session typesoffer a method for abstracting and validating structured communication sequences (sessions).Object-oriented programmingis an established paradigm for large scale applications.Union types, which behave as the least common supertypes of a set of classes, allow the implementation of unrelated classes with similar interfaces without additional programming. We have previously developed an integration of the features above into a class-based core language for building network applications, and this successfully amalgamated sessions and methods so that data can be exchanged flexibly according to communication protocols (session types).The first aim of the work reported in this paper is to provide a full proof of the type safety property for that core language by renewing syntax, typing and semantics. In this way, static typechecking guarantees that after a session has started, computation cannot get stuck on a communication deadlock.The second aim is to define a constraint-based type system that reconstructs the appropriate session types of session declarations instead of assuming that session types are explicitly given by the programmer. Such an algorithm can save programming work, and automatically presents an abstract view of the communications of the sessions.

scholarly journals Global progress for dynamically interleaved multiparty sessions

2014 ◽  
Vol 26 (2) ◽  
pp. 238-302 ◽  
Author(s):  
MARIO COPPO ◽  
MARIANGIOLA DEZANI-CIANCAGLINI ◽  
NOBUKO YOSHIDA ◽  
LUCA PADOVANI
Keyword(s):  
Type System ◽  
Single Session ◽  
Interaction Type ◽  
System A ◽  
Session Types ◽  
Global Type ◽  
Structured Communication

A multiparty session forms a unit of structured communication among many participants which follow communication sequences specified as a global type. When a process is engaged in two or more sessions simultaneously, different sessions can be interleaved and can interfere at runtime. Previous work on multiparty session types has ignored session interleaving, providing a limited progress property ensured only within a single session, by assuming non-interference among different sessions and by forbidding delegation. This paper develops, besides a more traditional, compositionalcommunicationtype system, a novel staticinteractiontype system for global progress in dynamically interleaved and interfered multiparty sessions. The interaction type system infers causalities of channels making sure that processes do not get stuck at intermediate stages of sessions also in presence of delegation.

scholarly journals The recursive record semantics of objects revisited

2004 ◽  
Vol 14 (3) ◽  
pp. 263-315 ◽  
Author(s):  
GÉRARD BOUDOL
Keyword(s):  
Type System ◽  
Object Oriented ◽  
Expressive Power ◽  
Object Oriented Programming ◽  
Principal Type ◽  
Core Language

In a call-by-value language, representing objects as recursive records requires using an unsafe fixpoint. We design, for a core language including extensible records, a type system which rules out unsafe recursion and still supports the construction of a principal type for each typable term. We illustrate the expressive power of this language with respect to object-oriented programming by introducing a sub-language for “mixin-based” programming.

Performance of Large-Scale Seasonal Thermal Energy Stores

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
F. Ochs ◽  
W. Heidemann ◽  
H. Müller-Steinhagen
Keyword(s):  
Thermal Energy ◽  
Large Scale ◽  
Fossil Fuels ◽  
Waste Heat ◽  
Type System ◽  
Solar Thermal Energy ◽  
Construction Costs ◽  
The Past ◽  
Energy Stores ◽  
Construction Type

More than 30 international research and pilot seasonal thermal energy stores (TESs) were realized within the past 30 years. Experiences with operation of these systems show that TES are technically feasible and work well. Seasonal storage of solar thermal energy or of waste heat from heat and power cogeneration plants can significantly contribute to substitute fossil fuels in future energy systems. However, performance with respect to thermal losses and lifetime has to be enhanced, while construction costs have to be further reduced. This paper gives an overview about the state-of-the-art of seasonal thermal energy storage with the focus on tank and pit TES construction. Aspects of TES modeling are given. Based on modeled and measured data, the influence of construction type, system configuration, and boundary conditions on thermal losses of large-scale TES is identified. The focus is on large-scale applications with tank and pit thermal energy stores and on recent investigations on suitable materials and constructions. Furthermore, experiences with the operation of these systems with respect to storage performance are discussed.

A High Density WSN Cluster Positioning Approach

2021 ◽  
Vol 12 (2) ◽  
pp. 1-17
Author(s):  
Qinqing Kang
Keyword(s):  
Large Scale ◽  
Attenuation Factor ◽  
Cluster Head ◽  
High Density ◽  
Wireless Sensor ◽  
Programming Algorithm ◽  
Localization Algorithm ◽  
Network Applications ◽  
Topology Information ◽  
Cluster Location

Node self-positioning is one of the supporting technologies for wireless sensor network applications. In this paper, a clustering localization algorithm is proposed for large-scale high-density wireless sensor networks. Firstly, the potential of the node is defined as the basis for the election of the cluster head. The distance between the nodes in the network is calculated indirectly by the relationship between the received signal strength and the communication radius. The topology information in each cluster is saved by the cluster head, and the linear programming method is used in the cluster head to implement the cluster internal relative positioning. Then, from the sink node, the inter-cluster location fusion is gradually implemented, and finally the absolute positioning of the whole network is realized. Compared with the centralized convex programming algorithm, the proposed algorithm has low computational complexity, small traffic, high positioning accuracy, and does not need to know the signal attenuation factor in the environment in advance, and there is anti-noise ability.

Object-Oriented Applications in Marine Hydrodynamics

2012 ◽  
Author(s):  
Piotr J. Bandyk ◽  
Justin Freimuth ◽  
George Hazen
Keyword(s):  
Large Scale ◽  
Object Oriented ◽  
System Of Systems ◽  
Object Oriented Programming ◽  
Marine Hydrodynamics ◽  
Natural Approach ◽  
Complex Problems ◽  
Systems Model

Object-oriented programming offers a natural approach to solving complex problems by focusing on individual aspects, or objects, and describing the ways in which they interact using interfaces. Modularity, extensibility, and code re-use often make OOP more appealing than its procedural counterpart. Code can be implemented in a more intuitive way and often mirrors the theory it derives from. Two examples are given in the form of real programs: a 3D panel code solver and a system-of-systems model for seabasing and environment sensing. Both are examples of large-scale frameworks and leverage the benefits offered by the object-oriented paradigm.

scholarly journals Designing Incentive Mechanisms for Mobile Crowdsensing with Intermediaries

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Yatong Chen ◽  
Huangxun Chen ◽  
Shuo Yang ◽  
Xiaofeng Gao ◽  
Yunhe Guo ◽  
...  
Keyword(s):  
Network Model ◽  
Large Scale ◽  
Incentive Compatibility ◽  
Rapid Development ◽  
Sensor Technology ◽  
Incentive Mechanisms ◽  
Mobile Crowdsensing ◽  
Network Applications ◽  
Sensing Platform

In the past decade, with the rapid development of wireless communication and sensor technology, ubiquitous smartphones equipped with increasingly rich sensors have more powerful computing and sensing abilities. Thus, mobile crowdsensing has received extensive attentions from both industry and academia. Recently, plenty of mobile crowdsensing applications come forth, such as indoor positioning, environment monitoring, and transportation. However, most existing mobile crowdsensing systems lack vast user bases and thus urgently need appropriate incentive mechanisms to attract mobile users to guarantee the service quality. In this paper, we propose to incorporate sensing platform and social network applications, which already have large user bases to build a three-layer network model. Thus, we can publicize the sensing platform promptly in large scale and provide long-term guarantee of data sources. Based on a three-layer network model, we design incentive mechanisms for both intermediaries and the crowdsensing platform and provide a solution to cope with the problem of user overlapping among intermediaries. We theoretically prove the properties of our proposed incentive mechanisms, including incentive compatibility, individual rationality, and efficiency. Furthermore, we evaluate our incentive mechanisms by extensive simulations. Evaluation results validate the effectiveness and efficiency of our proposed mechanisms.

Strategies for sustainable services in academic libraries

2016 ◽  
Vol 37 (6/7) ◽  
pp. 298-307
Author(s):  
Dianne Cmor
Keyword(s):  
Staff Development ◽  
Academic Libraries ◽  
Large Scale ◽  
University Libraries ◽  
Content Type ◽  
Sustainable Services ◽  
Technological University ◽  
Structured Communication ◽  
Practical Implications

Purpose The purpose of this paper is to explore distinctive yet simple strategies for sustainability in academic libraries focussing on structured communication templates for stakeholders, pre-planned daily programming, and regularized, self-sustaining staff development. Design/methodology/approach Case study of unique strategies implemented at Nanyang Technological University Libraries. Findings Each of the three strategies has been successfully launched though they are at various stages of maturity. The first two strategies (structured communication templates and daily programming) have been implemented quite recently, whereas the staff development programme has been running for some time. Findings indicate that sustainability in all of these cases is directly linked to good planning which either minimizes daily, weekly or monthly work, and/or helps to clarify goals and focus action. Practical implications These strategies are feasible, transferable, malleable, and impactful such that other academic libraries with varying staffing structures can adopt and adjust them to their local needs. Originality/value Implementing simple sustainable services and strategies can have real impact and can provide alternatives to large-scale projects that may be too resource intensive for many to undertake on a regular basis.

Japanese Politics in Transition: A Theoretical Review

1993 ◽  
Vol 28 (4) ◽  
pp. 443-455 ◽  
Author(s):  
Takashi Inoguchi
Keyword(s):  
Democratic Party ◽  
Large Scale ◽  
Type System ◽  
Liberal Democratic Party ◽  
Electoral System ◽  
Vice President ◽  
Liberal Democratic ◽  
Income Tax Law ◽  
Anglo American ◽  
Party Dominance

THE END OF ONE-PARTY DOMINANCE BY THE LIBERAL Democratic Party of Japan came as abruptly as the fall of the Berlin wall four years before. It started with the debate on electoral system change, ostensibly as an attempt to curb corruption. The LDP has been plagued by a series of large-scale corruption scandals since the Recruit scandal of 1989. The latest concerned former vice-president Shin Kanemaru's alleged violation of the political money regulation law and the income tax law in 1992–93. The Prime Minister, Kiichi Miyazawa, accepting a fair degree of compromise with opposition parties, wanted to pass a bill to change the current electoral system. The LDP initially wanted to change from the system of choosing a few persons in each district by one vote to the Anglo-American type system of selecting one person in each district by one vote. The opposition wanted to change to the continental European system of proportional representation. A compromise was made by the LDP's proposal to combine the latter two systems. Then two dissenting groups emerged suddenly in the LDP. One took the exit option by forming new political parties. The other took the voice option by backing away from the Miyazawa compromise plan. Miyazawa was humiliated by his failure to have the bill enacted and a motion of no confidence was passed. He then called for a general election, which took place on 18 July 1993. The outcome did not give a majority to the LDP and subsequently a non-LDP coalition was formed to produce a non-LDP government for the first time since the foundation of the LDP in 1955

scholarly journals Global escape in multiparty sessions

2014 ◽  
Vol 26 (2) ◽  
pp. 156-205 ◽  
Author(s):  
SARA CAPECCHI ◽  
ELENA GIACHINO ◽  
NOBUKO YOSHIDA
Keyword(s):  
Type System ◽  
Error Handling ◽  
Escape Mechanism ◽  
Session Types ◽  
Liveness Properties ◽  
Model Complex

This article proposes a global escape mechanism which can handle unexpected or unwanted conditions changing the default execution of distributed communicational flows, preserving compatibility of the multiparty conversations. Our escape is realized by a collection of asynchronous local exceptions which can be thrown at any stage of the communication and to any subsets of participants in a multiparty session. This flexibility enables to model complex exceptions such as criss-crossing global interactions and error handling for distributed cooperating threads. Guided by multiparty session types, our semantics is proven to provide a termination algorithm for global escapes. Our type system guarantees further safety and liveness properties, such as progress within the session and atomicity of escapes with respect to the subset of involved participants.

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