Improving the Requirements Engineering Process for an Electronic

engineering process for a telecommunications electronic clearinghouse that connects multiple trading partners. Software failures and faults were traced back to problems in the semi-structured requirements, which were written as message specifications (called "business rules") in a nonstandardized format using MS Word. To remedy these problems, we first designed a highly structured representation of the essential information in eXtensible Markup Language (XML), supported by XML Schema for precisely defining the requirements structure. Second, we developed XLEdit--- a custom GUI for editing the XML documents in a friendly way while preserving their information structure. Third, to assist the requirements engineers with automated migration of the existing business rules, we developed a converter for translating from MS Word to the target XML format. The investment in the technology for structured requirements editing and validation is expected to increase customer satisfaction and dramatically improve the efficiency of the clearinghouse service

XML-Based Requirements Engineering for an Electronic Clearinghouse

We present methods and tools to support XML-based requirements engineering for an electronic clearinghouse that connects trading partners in the telecommunications area. The original semi-structured requirements, locally known as business rules, were written as message specifications in a non-standardized and error-prone format using MS Word. To remedy the resulting software failures and faults, we first formalized the requirements by designing an W3C XML Schema for the precise definition of the requirements structure. The schema allows a highly structured representation of the essential information in eXtensible Markup Language (XML). Second, to offer the requirements engineers the ability to edit the XML documents in a friendly way while preserving their information structure, we developed a custom editor called XLEdit. Third, by developing a converter from MS Word to the target XML format, we helped the requirements engineers to migrate the existing business rules. Fourth, we developed translators from the structured requirements to schema languages, which enabled automated generation of message-validation code. The increase in customer satisfaction and clearinghouse-service efficiency are primary gains from the investment in the technology for structured requirements editing and validation

Lessons Learned From Automating Tests for an Operations Support System

this paper uses SilkTest scripts as the drivers of the OSS GUIs. These GUIs supply data for issuing requests and queries to the local SOA/LSMS database. Both NPAC and NEM are simulated in the test system, with simulators responding to SOA/LSMS requests and audits. Although it may be technically feasible to drive both NEM and NPAC simulators GUIs by SilkTest (as shown by dashed lines), our tests focused on the OSS in both initiating the test sequences (i.e., applying inputs and data to OSS) and verifying the test results (e.g., "a subscription version with the status of Pending created in the NPAC simulator"). In particular, the developed test cases are self-checking in that they verify their results by doing local or remote queries to the SOA/LSMS database or the NPAC simulator, respectively. The results of these queries are then automatically checked on the OSS GUI against the expected ones by the appropriate SilkTest script. In this way, back-end flow testing uses the GUI for supplying test input data and retrieving test output data from the SU

Improving the Requirements Engineering Process for an Electronic Clearinghouse

engineering process for a telecommunications electronic clearinghouse that connects multiple trading partners. Software failures and faults were traced back to problems in the semi-structured requirements, which were written as message specifications (called "business rules") in a nonstandardized format using MS Word. To remedy these problems, we first designed a highly structured representation of the essential information in eXtensible Markup Language (XML), supported by XML Schema for precisely defining the requirements structure. Second, we developed XLEdit--- a custom GUI for editing the XML documents in a friendly way while preserving their information structure. Third, to assist the requirements engineers with automated migration of the existing business rules, we developed a converter for translating from MS Word to the target XML format. The investment in the technology for structured requirements editing and validation is expected to increase customer satisfaction and dramatically improve the efficiency of the clearinghouse service

SCTP Subflows for Survivable FCS Applications

The Stream Control Transmission Protocol (SCTP), a general-purpose transport layer protocol standardized by the IETF, has been a promising candidate to join UDP and TCP as a core protocol. The new SCTP features such as multi-homing, multi-streaming, and enhanced security can significantly improve the performance of FCS applications. Multi-streaming provides an aggregation mechanism in an SCTP association to accommodate heterogeneous objects, which belong to the same application but may require different type of QoS from the network. However, the current SCTP specification lacks an internal mechanism to support the preferential treatment among its streams. We introduce the concept of subflow and propose to modify the current SCTP such that the streams are grouped into several subflows according to their required QoS. It is also proposed that each subflow should implement its own congestion control to prevent the so-called false sharing. To compare the throughput differences, analytic models have been derived for the current SCTP and for the subflow-capable SCTP with different congestion control mechanisms. Simulations with ns-2 have been used to qualitatively demonstrate the throughput differences of these designs in a simplified diff-serv network. The analytical models are confirmed to accurately reflect the SCTP behavior. The simulation also shows that our proposed solution is able to efficiently support QoS among the SCTP streams

Random-Walk Based Analysis of Virtual Backbone in MANETs

Service discovery architectures and cluster-assisted routing protocols in mobile ad-hoc networks (MANETs) heavily rely on formation and maintenance of a virtual backbone (VB). We present a novel analytic model for VB stability in MANETs. The model employs the dynamics of node movements, where link creation/failure is modeled via a random walk with probabilistic state-transition matrix. The backbone formation algorithm gives preference to the nodes with the smaller number of link changes and the higher degree. Therefore, the link arrivals and departures approximate the probability (and thus the expected time) for a mobile node to leave, join, or remain in the backbone, i.e., the stability of a dynamic structure of VB nodes

Analytical Model of a Virtual Backbone Stability in Mobile Environment

We present a probabilistic model of the stability of a virtual backbone in ad hoc networks. The model allows the computation of several metrics characterizing the dynamics of a node's random movement: (1) average time for the number of link changes of the node (i.e., instances of link creation and failure) or just failures to either drop below or exceed a given threshold, and, analogously, (2) average time for the number of active links of the node to either drop below or exceed a given threshold. The former defines the stability of the node's links and the latter is the node's degree (the number of active neighbors). Besides the stability of a virtual backbone, our model will help analyze the performance of various paradigms that rely on such link-based mobility metrics including some backbone- or clusterassisted routing protocols and service discovery architectures

Software---Practice And Experience

this paper uses SilkTest scripts as the drivers of the OSS GUIs. These GUIs supply data for issuing requests and queries to the local SOA/LSMS database. Both NPAC and NEM are simulated in the test system, with simulators responding to SOA/LSMS requests and audits. Although it may be technically feasible to drive both NEM and NPAC simulators GUIs by SilkTest (as shown by dashed lines), our tests focused on the OSS in both initiating the test sequences (i.e., applying inputs and data to OSS) and verifying the test results (e.g., "a subscription version with the status of Pending created in the NPAC simulator"). In particular, the developed test cases are self-checking in that they verify their results by doing local or remote queries to the SOA/LSMS database or the NPAC simulator, respectively. The results of these queries are then automatically checked on the OSS GUI against the expected ones by the appropriate SilkTest script. In this way, back-end flow testing uses the GUI for supplying test input data and retrieving test output data from the SU