Interaction techniques in desktop virtual environment: the study of visual feedback and precise manipulation method

Gesture-based systems allow users to interact with a virtual reality application in a natural way. Visual feedback for the gesture-based interaction technique has an impact on the performance and the hand instability making the manipulation of the object less precise. This paper investigated two new interaction techniques in a virtual environment. It describes the influence of natural and non-natural virtual feedback in the selection process using the GITDVR-G interaction technique, which consists of a grasping visual feedback. The GITDVR-G was evaluated in a virtual knee surgery training system. The results showed that it was effective in terms of the task completion time, and that the participants preferred the natural grasping visual feedback. Besides that, the precise manipulation in a newly-designed interaction technique (Precise GITDVR-G) was evaluated. The Precise GITDVR-G includes a normal manipulation mode and a precise manipulation mode that can be triggered by hand gestures. During the precise manipulation mode, an inset view will appear and move with the selected object to provide a better view to users, while the movements of the virtual hand are scaled down to improve the precision. Four different configurations of the precise manipulation technique were evaluated, and the results showed that the unimanual control method with an inset view performed better in terms of the task performance time and the subjective feedback. The finding suggested that the realistic virtual grasping visual feedback can be applied in a virtual hand interaction technique, and that the inset view feature is helpful in the precise manipulation.     

The preparation and morphology of PPO–epoxy blends

Poly(phenylene oxide) (PPO) was found to be miscible in diglycidyl ether of bisphenol A (DGEBA) based epoxy. The PPO–DGEBA system exhibited upper critical solution temperature (UCST) behavior. The cloud point temperatures were measured and found to be sensitive to the mol wt of the epoxy resin. A series of PPO-modified epoxies were cured with piperidine at 160°C, which is above the cloud point temperature. Upon cure, two phase solids were formed, which contained discrete PPO particles. However, the two-phase particulate morphology was not uniform and numerous large, occluded PPO particles were observed. In order to improve the uniformity, several styrene-maleic anhydride copolymers were evaluated as potential surfactants for PPO-DGEBA bends. The formation of a uniform, particulate morphology was facilitated by the addition of a styrene–maleic anhydride copolymer, containing a 10:1 ratio of styrene to maleic anhydride. To our knowledge, this is the first time that an emulsifying agent has been added to improve the morphology of thermoplastic modified epoxies. © 1993 John Wiley & Sons, Inc.     

Automatic analysis of deep-water remotely operated vehicle footage for estimation of Norway lobster abundance

Underwater imaging is being used increasingly by marine biologists as a means to assess the abundance of marine resources and their biodiversity. Previously, we developed the first automatic approach for estimating the abundance of Norway lobsters and counting their burrows in video sequences captured using a monochrome camera mounted on trawling gear. In this paper, an alternative framework is proposed and tested using deep-water video sequences acquired via a remotely operated vehicle. The proposed framework consists of four modules: (1) preprocessing, (2) object detection and classification, (3) object-tracking, and (4) quantification. Encouraging results were obtained from available test videos for the automatic video-based abundance estimation in comparison with manual counts by human experts (ground truth). For the available test set, the proposed system achieved 100% precision and recall for lobster counting, and around 83% precision and recall for burrow detection.     

Severe liver failure due to influenza A infection in a hemodialysis patient

Patients with influenza infection most commonly present with upper and occasionally lower respiratory tract symptoms. However, extrapulmonary presentations such as hepatitis are infrequently observed. We report a case of a hemodialysis patient with influenza A infection who presented with severe hepatitis and liver failure, while his respiratory symptoms were mild. It is important to recognize influenza infection as an unexplained cause of hepatitis and liver failure. In our case, liver failure resolved with supportive treatment.     

VISCOSITY STUDIES OF SYSTEM CaO-MgO-Al2O3-SiO2: II,CaO-Al2O3-SiO2*

Viscosity data are presented covering those compositions in the CaO-Al₂O₃-SiO₂ system which are liquid at 1500°C. The pattern of isokoms on the CaO-Al₂O₃-SiO₂ face of the compositional tetrahedron which represents the CaO-MgO-Al₂O₃-SiO₂ system is a system of lines which roughly parallel the lines along which the lime content is constant. There are, however, considerable deviations from this parallelism in regions of very low and very high alumina content.     

The impacts of asset impairments on performance in the Taiwan listed electronics industry

This paper explores whether the recognition of asset impairments provides an opportunity for earnings management by examining changes in the performance. First, we apply a dynamic data envelopment analysis model to evaluate the operating performance of Taiwanese electronics firms for the period from 2004 to 2013. Statistical tests are next applied to assess the average efficiency variation between the periods before and after firms recognise asset impairments. Several empirical findings are as follows: managers recognise asset impairments when their firms have poor performance as compared to other firms that do not record any asset impairments recognition, and that their performance keeps on improving in both the year of recognising asset impairments and the year after asset impairments recognition. That is, managers tend to recognise asset impairments to improve operating performance, while the firms are performing poorly, supporting the opportunistic behaviour theory.     

北京延庆创意园区总体规划

北京延庆创意园区的设计是绿化带与城市结构的双重压缩。城市结构的压缩创造了一个紧密强化的城市环境。城市结构的边缘由相互交织基础创意产业带和配套设施带组成,从而创造了一系列开放空间。景观的压缩使绿化带集中,得以最大化,同时合理利用了基地现有自然。增加的绿化带和公园提供了一个广阔的绿色环境。     

Toughening mechanisms in a multi-phase alloy of nylon 6,6/polyphenylene oxide

Toughening mechanisms in a nylon 6,6/polyphenylene oxide (PA/PPO) alloy are studied. This alloy consists of well dispersed PPO particles (containing an elastomeric phase) in a PA matrix. Both crazing and shear yielding mechanisms are found to be sequentially operative in this alloy. When a crack propagates in the material, a crazed zone forms ahead of the crack tip. This crazed zone then transforms into a shear yielded zone as the crack propagates through it. The crazes inside the original crazed zone are closed or distorted by the shear yielding process. In the transformed region, the shear yielded material is oriented at different angles as the crack propagates. These findings are consistent with the notion that hydrostatic tension has to be dissipated in order for the remaining deviatoric stress to reach the critical value for yielding. It is possible to partially attribute the increase in toughness to both crack blunting and zone shielding mechanisms.