Addressing performance requirements in the FDT-based design of distributed systems

The development of distributed systems is generally regarded as a complex and costly task, and for this reason formal description techniques such as LOTOS and ESTELLE (both standardized by the ISO) are increasingly used in this process. Our experience is that LOTOS can be exploited at many stages on the design trajectory, from requirements specification to implementation, but that the language elements do not allow direct formalization of performance requirements. To avoid duplication of effort by using two formalisms with distinct approaches, we propose a design method that incorporates performance constraints in an heuristic but effective manner

Detector Construction Management and Quality Control: Establishing and Using a CRISTAL System

The CRISTAL (Cooperating Repositories and an Information System for Tracking Assembly Lifecycles) project is delivering a software system to facilitate the management of the engineering data collected at each stage of production of CMS. CRISTAL captures all the physical characteristics of CMS components as each sub-detector is tested and assembled. These data are retained for later use in areas such as detector slow control, calibration and maintenance. CRISTAL must, therefore, support different views onto its data dependent on the role of the user. These data viewpoints are investigated in this paper. In the recent past two CMS Notes have been written about CRISTAL. The first note, CMS 1996/003, detailed the requirements for CRISTAL, its relationship to other CMS software, its objectives and reviewed the technology on which it would be based. CMS 1997/104 explained some important design concepts on which CRISTAL is and showed how CRISTAL integrated the domains of product data man- agement and workflow management. This note explains, through the use of diagrams, how CRISTAL can be established for detector production and used as the information source for analyses, such as calibration and slow controls, carried out by physicists. The reader should consult the earlier CMS Notes and conference papers for technical detail on CRISTAL - this note concentrates on issues surrounding the practical use of the CRISTAL software.Comment: 16 pages, 14 figure

모듈러 제품군 운영을 위한 다양성 관리 방법론

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 산업공학과, 2021. 2. 홍유석.글로벌 제조업체들은 다양한 제품을 출시하기 위해 모듈러 디자인 전략을 제품개발에 적용해왔다. 모듈러 디자인 전략은 제품을 모듈 단위로 구분한 후, 여러 종류의 모듈을 조합하여 새로운 제품을 만드는 전략이다. 모듈러 디자인은 제조업체가 제품다양성을 달성할 수 있도록 하였지만, 제공하는 제품의 수가 무수히 많아지면서 제품다양성으로 인한 안 좋은 영향들이 설계 영역뿐만 아니라, 시장, 생산 영역에서 지속적으로 발생하고 있는 실정이다. 따라서, 본 논문에서는 제품다양성의 안 좋은 영향을 줄일 수 있도록 이를 체계적으로 개발하고 운영하는 다양성 관리(variety management) 방법론을 제안한다. 다양성 관리를 성공적으로 수행하기 위해서는 교차영역 관점과 변종 수준 관점의 접근이 필요하다. 교차영역 관점은 제품다양성이 영향을 미치는 시장, 설계, 생산 영역의 요소들의 연결관계를 정립하는 메커니즘을 제공하며, 변종 수준 관점은 일반적인 요소(elements) 수준에서 한 단계 내려가 다양성 관리에 실제 문제가 되는 각 요소들의 변종들(variants)을 체계적으로 관리할 수 있도록 한다. 이 두 가지 관점에서, 본 논문은 다양성 관리에서 중요하게 다루어야 할 세 가지 과제–예상치 못한 변종의 발생 방지, 설계 복잡성 감축, 시장 점유율과 복잡성 비용 사이의 균형 잡기–를 해결하기 위한 방법론을 제안한다. 첫 번째 주제에서는, 아키텍처 기반의 접근법을 활용한 변종 관리 아키텍처(VA, variation architecture)를 도입하여 예상치 못한 변종의 발생을 방지하고자 한다. 개발 아키텍처는 모듈러 제품군을 개발할 때 사용하는 일종의 참조 아키텍처로, 시장 속성, 설계 모듈, 생산 설비의 연결관계를 정의하는 교차영역 연결 메커니즘을 제공한다. 변종 관리 아키텍처에서는 일반 수준의 계획과 변종 수준의 계획을 함께 세울 수 있다. 일반 수준에서는 요소 간 연결관계의 종류를 정의하여 제품군의 다양성 수준을 결정하고, 변종 수준에서는 변종들 간의 조합 규칙을 설정하여 불필요한 변종의 발생을 최소화한다. 또한, 본 연구에서는 제조업체가 변종 관리 아키텍처를 활용할 수 있도록 아키텍처 구축 프레임워크를 제안한다. 사례 연구에서는 자동차 프론트섀시 제품군을 통해 제품 및 변종의 수를 상당히 줄일 수 있음을 보여 줌으로써 프레임워크의 실용성을 검증한다. 다음으로, 인터페이스 표준화 개념을 적용하여 변종들 간의 복잡한 관계로부터 발생하는 설계 복잡성을 줄이는 연구를 수행한다. 본 연구에서 제안하는 인터페이스 설계 방법론은 하나가 아닌 다수의 표준 인터페이스를 사용하도록 허용한다. 모듈 변종들을 연결하기 위해 다수의 인터페이스를 도입하면, 인터페이스의 수와 적용범위에 따라 모듈러 제품군의 전체 구조가 달라지고 설계 복잡성 또한 다양한 양상으로 발생한다. 이를 측정하기 위해, 본 연구에서는 인터페이스의 선택에 영향을 받는 두 가지 복잡성 지표를–인터페이스 표준화 복잡성과 통합 복잡성을–정의한다. 인터페이스 표준화 복잡성은 표준 인터페이스를 설계할 때, 모듈 변종 설계자 간의 조율에 필요한 맨아워(person-hour)를 계산하고, 통합 복잡성은 각각의 모듈 변종과 인터페이스를 통합된 제품으로 설계하는데 필요로 하는 노력의 양으로, 위상적 복잡성(topological complexity) 지표를 기반으로 측정한다. 본 연구에서는 두 가지 복잡성을 최소화하는 인터페이스 설계 대안을 찾기 위한 프레임워크를 제공한다. 사례 연구에서 이의 적용성을 보여주기 위해 프론트섀시 제품군에 맞는 최적의 인터페이스 수와 제품군 구조를 도출한다. 마지막 주제에서는, 시장 점유율과 복잡성 비용의 균형을 맞추는 최적 제품 종수를 찾기 위한 최적화 모델을 개발한다. 최적화 모델은 제품을 구성하는 모듈 변종을 기반으로 모델링되고, 제품 및 모듈 종수가 증가함에 따라 시장 점유율의 증가분이 줄어들고, 반대로 복잡성 비용의 증가분은 늘어나는 특성을 반영한다. 시장 점유율을 구하기 위해 네스티드 로짓 모델(nested logit model)을 기반으로 하는 수요 모델을 개발한다. 네스티드 로짓 모델에서는 동일 제품군 내 제품들의 유사성을 고려하여 시장 점유율의 증가분이 줄어드는 특성을 반영한다. 다음으로, 제로베이스 원가계산 접근법(zero-based costing approach)을 활용한 복잡성 비용 모델을 도입한다. 이 접근법에서는 제품 혹은 모듈의 종수가 한 단위씩 늘어날 때 발생하는 비용을 단계적으로 계산하는 방법을 사용한다. 마지막으로, 수요 모델과 복잡성 비용 모델을 합친 최적화 모델(optimization model)을 모델링하여 최적 제품 종수와 제품의 모듈 구성을 도출하는 연구를 수행한다. 사례 연구에서는 민감도 분석을 수행하여 각 상황별 최적해가 어떻게 달라지는 지 보여주어 연구에서 제안하는 모델들의 효과를 검증한다.Global manufacturing companies have been achieving product variety by implementing a modular design strategy in which product variants are created by combining, adding, or substituting modules. Providing a high variety of products, however, causes negative effects not only on design but also on market and production. Variety management that defines the right range of variants is one of the most critical issues for most of the manufacturing companies. This thesis aims to propose methodologies that enable companies to systematically reduce negative effects of variety. In order to achieve successful variety management, this study approaches the issue from two viewpoints: cross-domain and variant-level viewpoints. A cross-domain viewpoint supports establishing relationships between elements in market, design, and production domain that are affected by product variety, and a variant-level viewpoint enables to explicitly manage variants of elements that are the main source of negative effects. In these viewpoints, this thesis focuses on dealing with three important challenges in variety management: to prevent unexpected variants, to reduce design complexity, and to balance market share and complexity cost. In the first theme, an architecture-based approach named variation architecture is introduced to prevent unexpected variants. Variation architecture (VA) is defined as a reference architecture for a modular product family providing the scheme by which variants in market, design, and production domain are arranged by cross-domain mapping mechanisms. The VA consists of generic-level and variant-level plans. At the generic-level, mapping types between domain elements are determined, and at the variant-level, combination rules between variants are set to reduce unexpected variants. Then, a framework is proposed to increase the practicality of the VA so that its compositions are well defined. In the case study, the framework is applied to an automobile front chassis family. The result shows that the number of module variants is significantly reduced compared to the current number of variants in operation. Secondly, the concept of interface standardization is introduced to manage design complexity caused by complicated combinations between module variants. This theme proposes an interface design methodology that addresses multiple standard interfaces in a modular product family. A product family structure is changed by implementing multiple standard interfaces, generating design complexity. This study defines two complexities resulting from the introduction of multiple standard interfaces: standardization effort and integration effort. Standardization effort is estimated as a required person-hours for coordinating module variants to design a standard interface, and integration effort is measured as an effort to integrate all design elements based on the concept of topological complexity. A framework is proposed to identify an optimal product family structure that minimizes the two complexities. In the case study, the proposed framework identifies an optimal structure and the number of standard interfaces for the front chassis family. Then, the study conducts a sensitivity analysis to demonstrate the methodologys applicability in interface management. In the last theme, an optimization model is developed to identify an optimal product variety to balance market share and complexity cost. The model focuses on module variants, not just product variants, because a modular product family creates product variants by combining module variants. The model reflects the trends of concave increase in market share and convex increase in complexity cost as the number of variety increases. A demand model is developed by the nested logit model that shows the concavity of market share based on the similarity of product variants in the same family, and a complexity cost model is constructed by the zero-based costing approach that an incremental cost is estimated as a variant is added. Combining the models, an optimization model is formulated to find an optimal variety and configurations of product variants. The case study demonstrates the models effectiveness by analyzing optimal solutions in various situations.Abstract i Contents iv List of Tables viii List of Figures ix Chapter 1 Introduction 1 1.1 Variety Management 1 1.2 Variety Management Challenges 5 1.3 Research Proposal: How to Deal with the Challenges? 7 1.4 Structure of Thesis 10 Chapter 2 Literature Review 11 2.1 Variety Management Methodologies 11 2.1.1 Modular product family design 11 2.1.2 Product family architecture 13 2.1.3 Classification of the contributions 15 2.2 Modular Design and Complexity 17 2.2.1 Modular design 17 2.2.2 Interface design 19 2.2.3 Design complexity 20 2.3 Product Family Design and Variety 22 2.3.1 Product family design 22 2.3.2 Variety optimization 25 Chapter 3 Variation Architecture for Reducing the Generation of Unexpected Variants 29 3.1 Introduction 29 3.1.1 Generation of unexpected variants 29 3.1.2 Needs for a systematic approach 31 3.2 Variation Architecture (VA) 33 3.2.1 Generic-level planning 34 3.2.2 Variant-level planning 41 3.3 Framework for Planning Product Variety 46 3.4 Application 47 3.4.1 Case description 47 3.4.2 Construction of variation architecture (VA) 49 3.4.3 Result and discussion 53 3.5 Summary 57 Chapter 4 Variant-level Interface Design for Reducing Design Complexity 59 4.1 Introduction 59 4.2 Variant-level Interface Design 61 4.3 Interface Design Complexity 64 4.3.1 Standardization effort 66 4.3.2 Integration effort 71 4.4 Framework for Variant-level Interface Design 76 4.5 Case Study 79 4.5.1 Application of the framework 79 4.5.2 Analysis and discussion 84 4.6 Summary 88 Chapter 5 Optimizing Product Variety for Balancing Market Share and Complexity Cost 91 5.1 Introduction 91 5.2 Evidence of the impact of variety on market share 94 5.3 Planning of Product Configurations 96 5.3.1 Product family architecture 96 5.3.2 Product configuration 98 5.4 Variety Optimization Model 100 5.4.1 Demand model 100 5.4.2 Complexity cost model 104 5.4.3 Optimization model 108 5.5 Case Study 110 5.5.1 Case description 110 5.5.2 Data source 112 5.5.3 Optimization setting 113 5.5.4 Result 115 5.5.5 Discussion 118 5.6 Summary 122 Chapter 6 Conclusion 125 6.1 Summary of Contributions 125 6.2 Limitations and Future Research Directions 127 Bibliography 129 Appendix A Variant-level Plan of a Front Chassis Family 147 Appendix B Adjacency and Combination Matrices of a Front Chassis Family 151 국문초록 155Docto

Open predicate path expressions for distributed environments: notation, implementation, and extensions

This dissertation introduces open predicate path expressions --a non-procedural, very-high-level language notation for the synchronization of concurrent accesses to shared data in distributed computer systems. The target environment is one in which resource modules (totally encapsulated instances of abstract data types) are the basic building blocks in a network of conventional, von Neumann computers or of functional, highly parallel machines. Each resource module will contain two independent submodules: a synchronization submodule which coordinates requests for access to the resource\u27s data and an access-mechanism submodule which localizes the code for operations on that data;Open predicate path expressions are proposed as a specification language for the synchronization submodule and represent a blend of two existing path notations: open path expressions and predicate path expressions. Motivations for the adoption of this new notation are presented, and an implementation semantics for the notation is presented in the form of dataflow graphs;An algorithm is presented which will automatically synthesize an open predicate path expression into a dataflow graph, which is then implemented by a network of communicating submodules written in either a sequential or an applicative language. Finally, an extended notation for the synchronization submodule is proposed, the purpose of which is to provide greater expressive power for certain synchronization problems which are difficult to specify using path expressions alone

The quotient in preorder theories

Seeking the largest solution to an expression of the form Ax 64 B is a common task in several domains of engineering and computer science. This largest solution is commonly called quotient. Across domains, the meanings of the binary operation and the preorder are quite different, yet the syntax for computing the largest solution is remarkably similar. This paper is about finding a common framework to reason about quotients. We only assume we operate on a preorder endowed with an abstract monotonic multiplication and an involution. We provide a condition, called admissibility, which guarantees the existence of the quotient, and which yields its closed form. We call preordered heaps those structures satisfying the admissibility condition. We show that many existing theories in computer science are preordered heaps, and we are thus able to derive a quotient for them, subsuming existing solutions when available in the literature. We introduce the concept of sieved heaps to deal with structures which are given over multiple domains of definition. We show that sieved heaps also have well-defined quotients

The Quotient in Preorder Theories

Seeking the largest solution to an expression of the form A x <= B is a common task in several domains of engineering and computer science. This largest solution is commonly called quotient. Across domains, the meanings of the binary operation and the preorder are quite different, yet the syntax for computing the largest solution is remarkably similar. This paper is about finding a common framework to reason about quotients. We only assume we operate on a preorder endowed with an abstract monotonic multiplication and an involution. We provide a condition, called admissibility, which guarantees the existence of the quotient, and which yields its closed form. We call preordered heaps those structures satisfying the admissibility condition. We show that many existing theories in computer science are preordered heaps, and we are thus able to derive a quotient for them, subsuming existing solutions when available in the literature. We introduce the concept of sieved heaps to deal with structures which are given over multiple domains of definition. We show that sieved heaps also have well-defined quotients.Comment: In Proceedings GandALF 2020, arXiv:2009.0936

Standard practices for the implementation of computer software

A standard approach to the development of computer program is provided that covers the file cycle of software development from the planning and requirements phase through the software acceptance testing phase. All documents necessary to provide the required visibility into the software life cycle process are discussed in detail

Design and verification of the rollback chip using HOP: a case study of formal methods applied to hardware design

technical reportThe use of formal methods in hardware design improves the quality of designs in many ways: it promotes better understanding of the design; it permits systematic design refinement through the discovery of invariants; and it allows design verification (informal or formal). In this paper we illustrate the use of formal methods in the design of a custom hardware system called the 'Rollback Chip' (RBC), conducted using a simple hardware design specification language called 'HOP'. An informal description of the requirements of the RBC is first given, followed by a behavioral description of RBC stating its desired behavior. The behavioral description is refined into progressively more efficient designs, terminating in a structural description. Key refinement steps are based on system invariants that are discovered during the design, and proved correct during design verification. The first step in design verification is to apply a program called PARCOMP to derive a behavioral description from the structural description of the RBC. The derived behavior is then compared against the desired behavior using equational verification techniques. This work demonstrates that formal methods can be fruitfully applied to a non-trivial hardware design. It also illustrates the particular advantages of our approach based on HOP and PARCOMP. Last, but not the least, it formally verifies the RBC mechanism itself