Software engineering is a value-based contact sport

The theory that most current students get covers may be 15 percent of the activities they encounter in practice. Most of it is based on a model of software engineering as a set-piece job of deriving and verifying code from a static set of requirements. This was a good model in the 1970s, but it is way out of date now. We should try to educate them for the software engineering situations they will encounter in the future.     

The effect of culture on requirements: a value-based view of prioritization

This paper examines how culture affects requirements and their prioritization. We analyze the requirements of a mobile service, which were collected from Helsinki, Hong Kong, and Las Vegas. We argue that the current prioritization techniques for requirements do not sufficiently account for the cultural effects, nor does the literature offer information on ways of prioritizing such requirements according to users’ values. We see this as problematic because the literature suggests that culture should be viewed as a set of values. Our findings support the argument that we should use a value-based approach in prioritizing requirements. Furthermore, by focusing on the links between needs and values, we should be able to develop prioritization techniques not only for multicultural settings but also for information systems (IS) development projects that involve subcultures, such as adolescent users or members of specific organizations. Our findings show that this can be a powerful way of understanding the differences between various subcultures of IS users. In addition, we demonstrate how the laddering interviewing technique can be used to support this work. The proposed value-based requirements prioritization approach is also ready for industry applications and it is agnostic to the underlying IS development method used by developers.     

Scenario-based and value-based specification mining: better together

Specification mining takes execution traces as input and extracts likely program invariants, which can be used for comprehension, verification, and evolution related tasks. In this work we integrate scenario-based specification mining, which uses a data-mining algorithm to suggest ordering constraints in the form of live sequence charts, an inter-object, visual, modal, scenario-based specification language, with mining of value-based invariants, which detects likely invariants holding at specific program points. The key to the integration is a technique we call scenario-based slicing, running on top of the mining algorithms to distinguish the scenario-specific invariants from the general ones. The resulting suggested specifications are rich, consisting of modal scenarios annotated with scenario-specific value-based invariants, referring to event parameters and participating object properties. We have implemented the mining algorithm and the visual presentation of the mined scenarios within a standard development environment. An evaluation of our work over a number of case studies shows promising results in extracting expressive specifications from real programs, which could not be extracted previously. The more expressive the mined specifications, the higher their potential to support program comprehension and testing.     

Engaging multiple perspectives: A value-based decision-making model

In some decision contexts, such as a crisis or when confronted by a new or novel set of circumstances, people may be forced to make decisions with limited information or time available for analysis. In such contexts, the set of alternative solutions developed may be greatly affected by the personal values and the perspective those values precipitate. Being able to view the decision environment from multiple perspectives enhances the decision-maker's ability to make better-informed choices. This article introduces the value-based decision-making model that suggests that multiple perspectives may be achieved by considering a foundation of individual values. Empirical testing indicates that this model provides a viable framework that decision-makers and researchers can use to better understand and facilitate multiple perspectives in decision-making.     

Detecting value-based scalar dependence

Precise value-based data dependence analysis for scalars is useful for advanced compiler optimizations. The new method presented here for flow and output dependence uses Factored Use and Def chains (FUD chains), our interpretation and extension of Static Single Assignment. It is precise with respect to conditional control flow and dependence vectors. Our method detects dependences which are independent with respect to arbitrary loop nesting, as well as loop-carried dependences. A loop-carried dependence is further classified as being carried from the previous iteration, with distance 1, or from any previous iteration, with direction <. This precision cannot be achieved by traditional analysis, such as dominator information or reaching definitions. To compute anti- and input dependence, we use Factored Redef-Use chains, which are related to FUD chains. We are not aware of any prior work which explicitly deals with scalar data dependence utilizing a sparse graph representation. A preliminary version of this paper appeared in theSeventh Anual Workshop on Languages and Compilers for Parallel Computing, August 1994. Supported in part by NSF Grant CCR-9113885 and a grant from Intel Corporation and the Oregon Advanced Computing Institute.     

A value-based approach to the ex-ante evaluation of IT enabled business process improvement projects

In this study, we propose a value-based management approach for assessing the potential for process improvements enabled by an information technology (IT) solution. Based on activity based management concepts, we perform a granular, process level analysis on workflow structure and associated resource consumption to provide quantifiable measures of potential improvement prior to system implementation. The proof of concept of this approach is illustrated in a southern United States county in need of integrating different government branches through an ERP implementation. Based on prior research, we first provide a catalog of non-value added (NVA) activities that can be used in management control and governance procedures for the systematic identification of process inefficiencies. Next, by breaking down processes to the level of atomic activities, we show that minimizing NVA activities provides a systematic means to mitigate process inefficiencies. A significant observation is that different NVA activities may impact process performance to varying degrees. Consequently, line items in the request for proposals (RFP) should be weighted accordingly during the vendor selection process, contrary to the common practice of treating all line items equally.     

Agile MERODE: a model-driven software engineering method for user-centric and value-based development

Agile is often associated with a lack of architectural thinking causing technical debt but has the advantage of user centricity and a strong focus on value. Model-driven software engineering (MDSE) strongly performs for building a quality architecture and code, but lacks focus on user requirements and tends to consider development as a monolithic whole. The combination of Agile and MDSE has been explored, but a convincing integrated method has not been proposed yet. This paper addresses this gap by exploring the specific combination of MERODE—as an example of a proven MDSE method—with Scrum, a reference agile method offering a concrete (sprint-based) life cycle management on the basis of user stories. The method resulting of this integration is called Agile MERODE; it is driven by user stories, themselves associated with behavior-driven development scenarios. It allows for domain-driven design and permits fast development from domain models by means of code generation. An illustrative example further clarifies the practical application of Agile MERODE, while a case study shows the planning game application in the case’s context. While the approach, in its entirety, allows reducing technical debt by building the architecture in a logical, consistent and complete manner, introducing MDSE involves a trade-off with pure value-driven development. Agile MERODE contributes to the state of the art by showing how to increase user centricity in MDSE, how to align model-driven engineering with the Scrum cycle, and how to reduce the technical debt of agile developments yet remaining value-focused.

     

E-business differentiation through value-based trust

For e-business, location is irrelevant and competition is intense. To succeed in this environment, organizations must find new ways to differentiate themselves from their competition. One way to achieve e-business differentiation is to foster trust by building a perception of value congruence and avoiding a perception of value conflict. We explore how value congruence contributes to and how value conflict decreases trust in e-businesses. An experiment was conducted to examine the respective impacts of value congruence and value conflict on trust in an e-commerce setting. Our results show that, for e-businesses, value congruence has an enabling effect on trust while value conflict reduces trust. Such effects are strong enough to suggest that value congruence can be employed as an effective way for e-businesses to differentiate themselves while creating and sustaining competitive advantage. Managerial implications are drawn from our results.     

An adaptive reasoning approach towards efficient ordering of composite hypotheses

A Bayesian network is a knowledge representation framework for encoding both qualitative and quantitative probabilistic dependencies among a set of propositional (or random) variables. An important type of probabilistic inference in a Bayesian network is the derivation of the most probable composite hypotheses — a set of hypotheses composed of multiple variables in a network. Such a type of probabilistic inference, however, is computationally intractable. In this paper an adaptive reasoning approach based on qualitative interval arithmetic is proposed as a method of dealing with the computational problem. Using this approach, a qualitative boundary, which reflects the upper and lower limits of a posterior likelihood, can be derived for each composite hypothesis. The advantage ofbounding each composite hypothesis qualitatively is that the quantitative values of the posterior likelihoods are not all necessary in the course of an inference. Consequently, an exhaustive evaluation can be avoided. The complexity of the proposed approach can be demonstrated to be no worse than that of a direct computation and in some cases, the computation is only a small fraction of that required in a straightforward direct computation.This work was supported in part by a grant to Queens College from the General Research Branch, National Institute of Health under grant No. RR-07064, and in part by a grant from the City University of New York PSC-CUNY Research Award Program.     

From a simple elimination ordering to a strong elimination ordering in linear time

We present a linear time algorithm for transforming a simple elimination ordering of a strongly chordal graph into a strong elimination ordering.     

A hybrid particle swarm optimization approach for the sequential ordering problem

The sequential ordering problem is a version of the asymmetric travelling salesman problem where precedence constraints on vertices are imposed. A tour is feasible if these constraints are fulfilled, and the objective is to find a feasible solution with minimum cost.     

Genetic algorithm approach to a production ordering problem in an assembly process with constant use of parts

An optimal production scheduling problem for an assembly process with buffers at the input and output sides of a machine is dealt with. The problem has two kinds of constraints. One constraint is that the buffers' capacity is limited. The other constraint is that the cycle time of the worker is constant without waiting time. An optimal production ordering is determined, subject to these constraints, in such a way that the rate of use of parts to produce each product should be as constant as possible. A procedure to apply the genetic algorithm to this problem is shown. The operations of reproduction, crossover and mutation are presented. It is observed from numerical results that the genetic algorithm gives a better suboptimal solution than the greedy method.     

NBmalloc: Allocating Memory in a Lock-Free Manner

Efficient, scalable memory allocation for multithreaded applications on multiprocessors is a significant goal of recent research. In the distributed computing literature it has been emphasized that lock-based synchronization and concurrency-control may limit the parallelism in multiprocessor systems. Thus, system services that employ such methods can hinder reaching the full potential of these systems. A natural research question is the pertinence and the impact of lock-free concurrency control in key services for multiprocessors, such as in the memory allocation service, which is the theme of this work. We show the design and implementation of NBmalloc, a lock-free memory allocator designed to enhance the parallelism in the system. The architecture of NBmalloc is inspired by Hoard, a well-known concurrent memory allocator, with modular design that preserves scalability and helps avoiding false-sharing and heap-blowup. Within our effort to design appropriate lock-free algorithms for NBmalloc, we propose and show a lock-free implementation of a new data structure, flat-set, supporting conventional “internal” set operations as well as “inter-object” operations, for moving items between flat-sets. The design of NBmalloc also involved a series of other algorithmic problems, which are discussed in the paper. Further, we present the implementation of NBmalloc and a study of its behaviour in a set of multiprocessor systems. The results show that the good properties of Hoard w.r.t. false-sharing and heap-blowup are preserved.     

Output value-based initialization for radial basis function neural networks

The use of Radial Basis Function Neural Networks (RBFNNs) to solve functional approximation problems has been addressed many times in the literature. When designing an RBFNN to approximate a function, the first step consists of the initialization of the centers of the RBFs. This initialization task is very important because the rest of the steps are based on the positions of the centers. Many clustering techniques have been applied for this purpose achieving good results although they were constrained to the clustering problem. The next step of the design of an RBFNN, which is also very important, is the initialization of the radii for each RBF. There are few heuristics that are used for this problem and none of them use the information provided by the output of the function, but only the centers or the input vectors positions are considered. In this paper, a new algorithm to initialize the centers and the radii of an RBFNN is proposed. This algorithm uses the perspective of activation grades for each neuron, placing the centers according to the output of the target function. The radii are initialized using the center’s positions and their activation grades so the calculation of the radii also uses the information provided by the output of the target function. As the experiments show, the performance of the new algorithm outperforms other algorithms previously used for this problem.     

存储池:一种适合于编译器的存储管理方法

介绍开放源码编译器ORC中使用的存储管理方法:存储池.存储池不是一种通用的存储管理方法,但是它特别适合于编译器.在编译器这个应用场合下,存储池比通用的malloc/free存储管理机制具有十分明显的优点.具体表现为分配速度快、管理开销小、释放时间开销小以及没有内存泄漏的问题.     

MIMS: Towards a Message Interface Based Memory System

The decades-old synchronous memory bus interface has restricted many innovations in the memory system, which is facing various challenges （or walls） in the era of multi-core and big data. In this paper, we argue that a message- based interface should be adopted to replace the traditional bus-based interface in the memory system. A novel message interface based memory system called MIMS is proposed. The key innovation of MIMS is that processors communicate with the memory system through a universal and flexible message packet interface. Each message packet is allowed to encapsulate multiple memory requests （or commands） and additional semantic information. The memory system is more intelligent and active by equipping with a local buffer scheduler, which is responsible for processing packets, scheduling memory requests, preparing responses, and executing specific commands with the help of semantic information. Under the MIMS framework, many previous innovations on memory architecture as well as new optimization opportunities such as address compression and continuous requests combination can be naturally incorporated. The experimental results on a 16-core cycle-detailed simulation system show that： with accurate granularity message, MIMS can improve system performance by 53.21% and reduce energy delay product （EDP） by 55.90%. Furthermore, it can improve effective bandwidth utilization by 62.42% and reduce memory access latency by 51% on average.     

A Shapley value-based thermal-efficient workload distribution in heterogeneous data centers

The Journal of Supercomputing - Thermal-aware (TA) task allocation is one of the most effective software-based dynamic thermal management techniques to minimize energy consumption in data centers...     

VCS: value chains simulator, a tool for value analysis of manufacturing enterprise processes (a value-based decision support tool)

Manufacturing enterprises are facing a competitive challenge. This paper proposes the use of a value chain based approach to support the modelling and simulation of manufacturing enterprise processes. The aim is to help experts to make relevant decisions on product design and/or product manufacturing process planning. This decision tool is based on the value chain modelling, by considering the product requirements. In order to evaluate several performance indicators, a simulation of various potential value chains adapted to market demand was conducted through a Value Chains Simulator (VCS). A discrete event simulator is used to perform the simulation of these scenarios and to evaluate the value as a global performance criterion (balancing cost, quality, delivery time, services, etc.). An Analytical Hierarchy Process module supports the analysis process. The value chain model is based on activities and uses the concepts of resource consumption, while integrating the benefiting entities view point. A case study in the microelectronic field is carried out to corroborate the validity of the proposed VCS.     

An approximate solution to a jit-based ordering system

In this paper we consider a multi-stage multi-product production, inventory and transportation system including lot production processes and develop a goal programming model for a pull type ordering system based on the concept of a Just-In-Time(JIT) production system. We also present a pragmatic approach which reduces the required computational time for the formulated mixed integer goal programming problem using a mathematical programming modeling language. The proposed solution procedure is realized utilizing the post-optimal analysis which can be performed by the modeling language.