Complex and Composite Objects in CAD/CAM Databases

An essential modelling concept for CAD/CAM databases is the composition relationship which relates a superior composite object to its components and makes the component's data visible in the composite object. In order to import only the necessary information into the composite object, often an interface object is defined which is copied into the composite object as an abstraction of the component. In this paper an object oriented model is introduced which comprises an inheritance relationship between an inheritor object and a transmitter object. The inheritor object inherits (the existence of) attributes of the transmitter object, but moreover it also may inherit the attributes' values. This inheritance relationship can be used to model the notion of interface of an object as well as the composition relationship. Thus, by using the only concept of value inheritance it is possible to model all aspects of the composition of objects. Furthermore, some severe drawbacks of a rigid interface concept can be overcome by the inheritance relationship

A general model for version management in databases

In this paper we introduce a general model for version management expressed by the concept of version environments. A version environment offers two mechanisms for structuring the version sets of objects: graphs and partitions. By the use of views, constraints and transactions the version environment may be tailored to specific user requirements. The embedding of application tools into the version environment provides the users with their specific application environment which consists of the objects, their version structures and the tools operating on them. The proposed concept is more general and more powerful than the concepts published so far; it is shown, how well known version concepts can be implemented by means of version environments

A transaction model supporting complex applications in integrated information systems

The use of database systems in new applications, e.g. computer aided design, software engineering, etc, leads to new requirements for the transaction management. Main characteristics of such environments are long duration of transactions and teamwork. In this paper we introduce a concept for lang transactions which especially supports the cooperative work of groups on a common set of data. The transaction model has two levels: on the one hand the team has to be protected from the outside world, on the other hand mechanisms are required which allow controlled teamwork an common objects. In the latter case rigid synchronisation mechanisms as used in database systems are not applicable. A main concept for the support of teamwork and for design databases in general is a user-oriented version mechanism. This paper presents such a mechanism and its integration into the transaction model

Determining service provider and transport system related effects of ridesourcing services by simulation within the travel demand model mobiTopp

Purpose Ridesourcing services have become popular recently and play a crucial role in Mobility as a Service (MaaS) offers. With their increasing importance, the need arises to integrate them into travel demand models to investigate transport system-related effects. As strong interdependencies between different people’s choices exist, microscopic and agent-based model approaches are especially suitable for their simulation. Method This paper presents the integration of shared and non-shared ridesourcing services (i.e., ride-hailing and ride-pooling) into the agent-based travel demand model mobiTopp. We include a simple vehicle allocation and fleet control component and extend the mode choice by the ridesourcing service. Thus, ridesourcing is integrated into the decision-making processes on an agent’s level, based on the system’s specific current performance, considering current waiting times and detours, among other data. Results and Discussion In this paper, we analyze the results concerning provider-related figures such as the number of bookings, trip times, and occupation rates, as well as effects on other travel modes. We performed simulation runs in an exemplary scenario with several variations with up to 1600 vehicles for the city of Stuttgart, Germany. This extension for mobiTopp provides insights into interdependencies between ridesourcing services and other travel modes and may help design and regulate ridesourcing services

The measurement of visual ability in children with cerebral palsy : A systematic review

AIM To identify and evaluate measures of visual ability utilised with children with cerebral palsy (CP). METHOD Eight databases were searched for measures of visual ability. Key selection criteria for measures were: (1) use with children with CP, and (2) focus of visual ability measurement at Activities and Participation domain of the International Classification of Functioning, Disability and Health (ICF). The Consensus-based Standards for the Selection of Measurement Instruments (COSMIN) Checklist was used to assess psychometric properties. RESULTS From 6763 papers retrieved, 25 were relevant and 19 measures of visual ability were identified. Only ten measures were supported with evidence of validity or reliability. No discriminative measure analogous to existing CP functional classification systems was found. No outcome measure valid for evaluation of visual abilities of children with CP was found. INTERPRETATION Vision impairment is recognised as relevant to the functioning of children with CP, however measurement of vision is most often focused at Body Function levels, e.g. visual acuity. Measuring visual abilities in the Activities and Participation domain is important in considering how a child with CP functions in vision-related activities. The lack of psychometrically strong measures for visual ability is a gap in current clinical practices and research

Self-Regulating Demand and Supply Equilibrium in Joint Simulation of Travel Demand and a Ride-Pooling Service

This paper presents the coupling of a state-of-the-art ride-pooling fleet simulation package with the mobiTopp travel demand modeling framework. The coupling of both models enables a detailed agent- and activity-based demand model, in which travelers have the option to use ride-pooling based on real-time offers of an optimized ride-pooling operation. On the one hand, this approach allows the application of detailed mode-choice models based on agent-level attributes coming from mobiTopp functionalities. On the other hand, existing state-of-the-art ride-pooling optimization can be applied to utilize the full potential of ride-pooling. The introduced interface allows mode choice based on real-time fleet information and thereby does not require multiple iterations per simulated day to achieve a balance of ride-pooling demand and supply. The introduced methodology is applied to a case study of an example model where in total approximately 70,000 trips are performed. Simulations with a simplified mode-choice model with varying fleet size (0–150 vehicles), fares, and further fleet operators’ settings show that (i) ride-pooling can be a very attractive alternative to existing modes and (ii) the fare model can affect the mode shifts to ride-pooling. Depending on the scenario, the mode share of ride-pooling is between 7.6% and 16.8% and the average distance-weighed occupancy of the ride-pooling fleet varies between 0.75 and 1.17

Small-volume resuscitation with hyperoncotic albumin: a systematic review of randomized clinical trials

Background Small-volume resuscitation can rapidly correct hypovolemia. Hyperoncotic albumin solutions, long in clinical use, are suitable for small-volume resuscitation; however, their clinical benefits remain uncertain. Methods Randomized clinical trials comparing hyperoncotic albumin with a control regimen for volume expansion were sought by multiple methods, including computer searches of bibliographic databases, perusal of reference lists, and manual searching. Major findings were qualitatively summarized. In addition, a quantitative meta-analysis was performed on available survival data. Results In all, 25 randomized clinical trials with a total of 1,485 patients were included. In surgery, hyperoncotic albumin preserved renal function and reduced intestinal edema compared with control fluids. In trauma and sepsis, cardiac index and oxygenation were higher after administration of hydroxyethyl starch than hyperoncotic albumin. Improved treatment response and renal function, shorter hospital stay and lower costs of care were reported in patients with liver disease receiving hyperoncotic albumin. Edema and morbidity were decreased in high-risk neonates after hyperoncotic albumin administration. Disability was reduced by therapy with hyperoncotic albumin in brain injury. There was no evidence of deleterious effects attributable to hyperoncotic albumin. Survival was unaffected by hyperoncotic albumin (pooled relative risk, 0.95; 95% confidence interval 0.78 to 1.17). Conclusion In some clinical indications, randomized trial evidence has suggested certain benefits of hyperoncotic albumin such as reductions in morbidity, renal impairment and edema. However, further clinical trials are needed, particularly in surgery, trauma and sepsis

Chasing gravity's rainbow: Kwajalein and US ballistic missile testing

The international regime for controlling the spread of weapons of mass destruction is at a cross-roads. The existing Nuclear Non-Proliferation Treaty regime is inadequate to the task of controlling ballistic missile development, and these missiles are capable of delivering nuclear, as well as chemical and biological weapons. The superpowers are developing their ballistic missiles qualitatively even as they negotiate cuts in numbers in the START 1 agreement. Export controls on ballistic missile technology have not halted missile proliferation: many small and medium-sized states are developing their own ballistic missiles; space is quickly becoming accessible to many states for military purposes. This report is the product of phase one of a project conducted by Nautilus Pacific Research, to promote a Ballistic Missile Test Ban Treaty and to support international controls on ballistic missile development. It describes how ballistic missiles are tested, earlier ballistic missile testing in the Pacific area, US facilities for testing ballistic missiles (the USAKA installation on Kwajalein Atoll and the Western Test Range), the organisational links, and the implications for other programs, particularly the Strategic Defence Initiative. Finally, it discusses the various missile test ban proposals