A comparative study of strain relaxation effects on the performanceof InGaAs quantum-well-based heterojunction phototransistors

The performance of a GaAs based heterojunction phototransistors (HPTs) using an n-p-i-n configuration, where the absorption is provided by InGaAs quantum wells (QWs) have been studied. Structures with differing numbers of QW were investigated. This allowed the tradeoff between the benefits of increased light absorption and the drawbacks of increased lattice relaxation, caused by the mis-match between InGaAs and the GaAs substrate, to be examined. All the HPT's investigated showed responsivities (A/W) far larger than unity, as well as large wavelength tolerance, for example 44 A/W±15% from 950-970 nm, for 10 μW incident optical. Electrical common-emitter current gains, of up to 3000 were measured for our HPT's and then confirmed by subsequent HBT measurements. Small relaxation levels (<10%) had no significant detrimental effects, allowing a large improvement in HPT performance. More heavily relaxed HPTs showed a degradation in both the inherent photodetector and transistor action, though this was not catastrophic in nature. A simple simulation of the results is carried out, suggesting that the dislocations adversely effect the carrier transport across the collector region, and also reduce the minority carrier diffusion length in the base     

Development of a simple model for batch and boundary information updation for a similar ship’s block model

In early 2000,large domestic shipyards introduced shipbuilding 3D computer-aided design (CAD) to the hull production design process to define manufacturing and assembly information.The production design process accounts for most of the man-hours (M/H) of the entire design process and is closely connected to yard production because designs must take into account the production schedule of the shipyard,the current state of the dock needed to mount the ship’s block,and supply information.Therefore,many shipyards are investigating the complete automation of the production design process to reduce the M/H for designers.However,these problems are still currently unresolved,and a clear direction is needed for research on the automatic design base of manufacturing rules,batches reflecting changed building specifications,batch updates of boundary information for hull members,and management of the hull model change history to automate the production design process.In this study,a process was developed to aid production design engineers in designing a new ship’s hull block model from that of a similar ship previously built,based on AVEVA Marine.An automation system that uses the similar ship’s hull block model is proposed to reduce M/H and human errors by the production design engineer.First,scheme files holding important information were constructed in a database to automatically update hull block model modifications.Second,for batch updates,the database’s table,including building specifications and the referential integrity of a relational database were compared.In particular,this study focused on reflecting the frequent modification of building specifications and regeneration of boundary information of the adjacent panel due to changes in a specific panel.Third,the rollback function is proposed in which the database (DB) is used to return to the previously designed panels.     

Industrial aspects and literature survey: Fleet composition and routing

The purpose of this paper is to describe industrial aspects of combined fleet composition and routing in maritime and road-based transportation, and to present the current status of research in the form of a comprehensive literature review. First, presents a classification of problems, and then focuses on a basic definition of combined fleet composition and routing: the fleet size and mix vehicle routing problem. A basic mathematical formulation from the literature is presented. Further, the literature of extended and related problems is described and categorized. Surveys of application oriented research in road-based and maritime transportation conclude the review. Finally, we contrast the literature with aspects of industrial applications from a critical, but constructive stance. Major issues for future work are suggested.     

New method for selectivity enhancement of SiC field effect gas sensors for quantification of NO x

A silicon carbide based enhancement type metal insulator field effect transistor with porous gate metallization has been investigated as a total NO _x sensor operated in a temperature cycling mode. This operating mode is quite new for gas sensors based on the field effect but promising results have been reported earlier. Based on static investigations we have developed a suitable T-cycle optimized for NO _x detection and quantification in a mixture of typical exhaust gases (CO, C₂H₄, and NH₃). Significant features describing the shape of the sensor response have been extracted and evaluated with multivariate statistics (e.g. linear discriminant analysis) allowing quantification of NO _x . Additional cleaning-cycles every 30?min improve the stability of the sensor further. With this kind of advanced signal processing the influence of sensor drift and cross sensitivity to ambient gases can be reduced effectively. Measurements have proven that different concentrations of NO _x can be detected even in a changing mixture of other typical exhaust gases under dry and humid conditions. In addition to that, unknown concentrations of NO _x can be detected based on a small set of training data. It can be concluded that the performance of GasFETs for NO _x determination can be enhanced considerably with temperature cycling and appropriate signal processing.     

Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms

Standardised questionnaires for the analysis of musculoskeletal symptoms in an ergonomic or occupational health context are presented. The questions are forced choice variants and may be either self-administered or used in interviews. They concentrate on symptoms most often encountered in an occupational setting. The reliability of the questionnaires has been shown to be acceptable. Specific characteristics of work strain are reflected in the frequency of responses to the questionnaires.     

Influence of body segment dynamics on loads at the lumbar spine during lifting.

Flexion-extension moments acting at the L5/S1 level and hip joints were calculated using three different techniques; a pure static analysis, a static analysis including the inertial force of the load, and a dynamic analysis. Ten subjects participated in the study and were asked to lift a box weighing either 50 N or 150 N, using a freestyle technique. The lifts were performed at normal and fast speed. The intra-subject lifting techniques were consistent when lifting the same loads. The moments predicted by the dynamic analysis and the static analysis were the same when holding weights in static postures. When performing the lifts, differences in the peak moments occurred between static and dynamic analyses. These differences were influenced by external load and by lifting speed. Taking the effect of the inertia of load into account in the static analysis resulted in an increase in the moment magnitude, but the predicted moment was still much less than in the dynamic analysis which yielded the largest moment magnitudes. The difference between dynamic and static analysis was greatest when lifting 50 N at fast speed; an 87% increase in L5/S1 moment and a 95% increase in hip moment was observed when replacing the pure static with a dynamic analysis.     

Assigning real-time tasks on heterogeneous multiprocessors with two unrelated types of processors

Consider the problem of partitioned scheduling of an implicit-deadline sporadic task set on heterogeneous multiprocessors to meet all deadlines. Each processor is either of type-1 or type-2. We present a new algorithm, FF-3C, for this problem. FF-3C offers low time-complexity and provably good performance. Specifically, FF-3C offers (i) a time-complexity of O(n?max(m,logn)+m?logm), where n is the number of tasks and m is the number of processors and (ii) the guarantee that if a task set can be scheduled by an optimal partitioned-scheduling algorithm to meet all deadlines then FF-3C meets all deadlines as well if given processors at most $\frac{1}{1-\alpha}$ times as fast (referred to as speed competitive ratio) and tasks are scheduled using EDF; where α is a property of the task set. The parameter α is in the range (0,0.5] and for each task, it holds that its utilization is no greater than α or greater than 1?α on each processor type. Thus, the speed competitive ratio of FF-3C can never exceed 2. We also present several extensions to FF-3C; these offer the same performance guarantee and time-complexity but with improved average-case performance. Via simulations, we compare the performance of our new algorithms and two state-of-the-art algorithms (and variations of the latter). We evaluate algorithms based on (i) running time and (ii) the necessary multiplication factor, i.e., the amount of extra speed of processors that the algorithm needs, for a given task set, so as to succeed, compared to an optimal task assignment algorithm. Overall, we observed that our new algorithms perform significantly better than the state-of-the-art. We also observed that our algorithms perform much better in practice, i.e., the necessary multiplication factor of the algorithms is much smaller than their speed competitive ratio. Finally, we also present a clustered version of the new algorithm.     

From designing objects to designing fields—from control to freedom

In this paper we want to explore Field as a concept and as a metaphor for understanding interactive systems. By interactive systems we mean both systems and artworks, where the user by interacting changes the course of events. We intend to show why we need new terms and why we consider Field to be a fruitful concept and term. Further we will show how the Field concept changes both our understanding of what we do as designers and composers and how we acknowledge our audience. We will exemplify the design consequences of the Field concept by going through some design considerations we made when designing the audio tactile installation Mufi.