Modeling an Adaptive System with Complex Queuing Networks and Simulation

An adaptive system differs from a non-adaptive system in that an adaptive system uses a specific process to identify and implement adaptations to system parameters during run time in an effort to increase system performance.;In order to develop an adaptive system one of the most important aspects is the ability to accurately predict and manage system behavior. If an unexpected event has occurred, accurate prediction of system behavior is needed in order to determine whether or not the system is able to continually meet expectations and/or requirements. When considering any possible adaptations to the system, one must be able to accurately predict their consequences as well.;In a feedback loop of an adaptive system performance analysis and prediction performance analysis and prediction may lead to a large number of different states. Therefore, the method of analyzing the system must be fast. For complex systems, however, the most popular method for predicting performance is simulation. Simulations, depending on the size of the system, are known for being slow.;In this thesis we develop a fast method for prediction of performance of a complex system. We use this method to allocate resources to the system initially, and then make decisions for system adaptation during runtime. Finally we test various modifications to the system in order to measure the robustness of our method

Airspace Technology Demonstration 2 (ATD-2) Technology Description Document (TDD)

This Technology Description Document (TDD) provides an overview of the technology for the Phase 1 Baseline Integrated Arrival, Departure, and Surface (IADS) prototype system of the National Aeronautics and Space Administration's (NASA) Airspace Technology Demonstration 2 (ATD-2) project, to be demonstrated beginning in 2017 at Charlotte Douglas International Airport (CLT). Development, integration, and field demonstration of relevant technologies of the IADS system directly address recommendations made by the Next Generation Air Transportation System (NextGen) Integration Working Group (NIWG) on Surface and Data Sharing and the Surface Collaborative Decision Making (Surface CDM) concept of operations developed jointly by the Federal Aviation Administration (FAA) and aviation industry partners. NASA is developing the IADS traffic management system under the ATD-2 project in coordination with the FAA, flight operators, CLT airport, and the National Air Traffic Controllers Association (NATCA). The primary goal of ATD-2 is to improve the predictability and operational efficiency of the air traffic system in metroplex environments, through the enhancement, development, and integration of the nation's most advanced and sophisticated arrival, departure, and surface prediction, scheduling, and management systems. The ATD-2 project is a 5-year research activity beginning in 2015 and extending through 2020. The Phase 1 Baseline IADS capability resulting from the ATD-2 research will be demonstrated at the CLT airport beginning in 2017. Phase 1 will provide the initial demonstration of the integrated system with strategic and tactical scheduling, tactical departure scheduling to an en route meter point, and an early implementation prototype of a Terminal Flight Data Manager (TFDM) Electronic Flight Data (EFD) system. The strategic surface scheduling element of the capability is consistent with the Surface CDM Concept of Operations published in 2014 by the FAA Surface Operations Directorate

Verification and validation in software product line engineering

Verification and Validation (V&V) is currently performed during application development for many systems, especially safety-critical and mission-critical systems. However, the V&V process has been limited to single system development. This dissertation describes the extension of V&V from an individual application system to a product line of systems that are developed within an architecture-based software engineering environment.;In traditional V&V, the system provides the context under which the software will be evaluated, and V&V activities occur during all phases of the system development lifecycle. The transition to a product line approach to development removes the individual system as the context for evaluation, and introduces activities that are not directly related to a specific system. This dissertation presents an approach to V&V of software product lines that uses the domain model and the domain architecture as the context for evaluation, and enables V&V to be performed throughout the modified lifecycle introduced by domain engineering.;This dissertation presents three advances that assist in the adaptation of V&V from single application systems to a product line of systems. The first is a framework for performing V&V that includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The second is a detailed method to extend the crucial V&V activity of criticality analysis from single system development to a product line of systems. The third advance is an approach to enable formal reasoning, which is needed for high assurance systems, on systems that are based on commercial-off-the-shelf (COTS) products

Analysis of Airport Security Screening Checkpoints using Queuing Networks and Discrete Event Simulation: A Theoretical and Empirical Approach

This study utilized discrete event simulation (DES) and queuing networks to investigate the effects of baggage volume and alarm rate at the Security Screening Checkpoint (SSCP) of a small origin and destination airport. A Jackson queuing network was considered for a theoretical assessment to SSCP performance. A DES model using Arena version 12 was utilized for an empirical approach. Data was collected from both literature and by manual collection methods. Manual data was collected during the peak operating time of 6am-7am local time at the airport being modeled. The simulation model was verified and validated qualitatively and quantitatively by statistical testing before experimentation. After validation, a sensitivity analysis was performed on baggage volume of passengers (PAX) and the alarm rate of baggage screening devices, where SSCP throughput and PAX cycle time were the dependent measures. The theoretical queuing network approach proved an accurate method of predicting cycle time, but only under limited steady-state conditions. The empirical model and sensitivity analysis showed that SSCP performance is highly sensitive to alarm rate in both throughput and cycle time. Furthermore, empirical modeling and sensitivity analysis showed that SSCP performance was moderately sensitive to alarm rate, and completely resilient to the effects of baggage volume. Practical implications and future directions were also discussed at the conclusion of the study

Context-aware information in mobile devices

This paper describes a novel approach for indoor location and integration of other services in a university campus using Bluetooth Low Energy (BLE) devices. These BLE devices broadcast a Bluetooth signal in a limited and configured range/area, thus functioning as beacons that provide useful context-aware information to nearby devices operating with custom applications. Such applications can interpret the received signals as location and provide a range of useful services to the end user (students, events attendees), namely, indoor location and navigation or personalized complex workflows that require the interaction of the end user with multiple services within the university campus.info:eu-repo/semantics/acceptedVersio

Interoperability Among Heterogeneous Networks for Future Aeronautical Communications

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Sustainability Research of the Secure Wireless Communication System with Channel Reservation

The paper presents the research of the stability of the system with redundancy of communication channels. For this, two prototypes have been developed that are built (1) according to the classical circuit-switched scheme and (2) with aggregation of several virtual channels. Prototyping, installation on various vehicles and measurements of the stability of the entire system as a whole were carried out. The paper also presents structural diagrams, hardware, and a list of problems and difficulties that the authors encountered during the practical implementation and implementation of these systems. In the future, it is planned to expand the study of these systems when working with high-level channel virtualization and the search for methods to accelerate its work

Operating characteristics of passenger screening processes and the development of a paced inspection system

The airport checkpoint security screening (ACSS) system is an important line of defense against the introduction of dangerous objects into the U.S. aviation system. Recently, there has been much interest in modeling these systems and to derive operating parameters which optimize performance. In general there are two performance measures of interest (i) the waiting time of the arriving entities, and (ii) the allocated screening resources and its utilization. Clearly, the traveling public would like a zero waiting time, while airports are limited both in terms of space and resource capital. The arrival and exit entity in the ACSS system are passengers. On arrival, passengers split into two sub- entities (i) bags or other carry-on items and (ii) passenger body and the two must rejoin prior to exit. There is a 1:M ratio between passengers and carry-on items with M\u3e0. The existing knowledge base related to the operating characteristics of ACSS processes is very limited. Almost all screening systems have a human interpretive component, as a result the screening behavior is highly variant and difficult to predict. This dissertation studies the operating characteristics of the security screening process to develop proven relationships between inspection times and clearance rates. A descriptive model of the screening system, which identifies the design variables, operational parameters and performance measures, is defined. Screening data was collected from 18 U.S. airports (10 high volume, 5 medium volume, and 3 low volume). The data sets captured (i) passenger arrival times, (ii) X-ray inspection times, (iii) clearance decision, (iv) passenger physical inspection times, and (v) secondary carry-on item inspection times. An empirical analysis was used to generate a speed of inspection operating characteristic (SIOC) curve for each of the inspection processes. Mean inspection times are found to be much larger than what is frequently assumed in the literature. The findings showed that the inspection rate increases linearly with inspection time until the 7 second point, after which it describes a negative growth. The behavior of these relationships under different operating conditions was studied using a set of hypothesis. These include performance differences between airport types, between checkpoints within an airport, as well as the effect of increased passenger arrival rates. Reliable data describing the operating characteristics of security inspection processes are now available. This data can be used to design and analyze ACSS systems with much greater accuracy and detail. The results will in effect reduce the dependence on trial-and-error experiments at the site. A greater understanding of the statistical behavior of the inspection process is known and validated. The SIOC curves provide a standard against which new and alternative ACSS designs can be evaluated and benchmarked. Paced ACSS systems are demonstrated as a viable alternative with potentially higher performance