The right view from the wrong location: depth perception in stereoscopic multi-user virtual environments

Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion.     

Image coding algorithm based on Hadamard transform and simple vector quantization

Transform coding is commonly used in image processing algorithms to provide high compression ratios, often at the expense of processing time and simplicity of the system. We have recently proposed a pixel value prediction scheme in order to exploit adjacent pixel correlation, providing a low-complexity model for image coding. However, the proposed model was unable to reach high compression ratios retaining high quality of reconstructed image at the same time. In this paper we propose a new segmentation algorithm which further utilizes adjacent pixel correlation, provides higher compression ratios and it is based on application of Hadamard transform coding. Additional compression is provided by using vector quantization for a low number of quantization levels and by simplifying generalized Lloyd’s algorithm where the special attention is paid to determination of optimal partitions for vector quantization, making a fixed quantizer. The proposed method is quite simple and experimental results show that it ensures better or similar rate-distortion ratio for very low bit-rates, comparing to the other similar methods that are based on wavelet or curvelet transform coding and support or core vector machine application. Furthermore, the proposed method requires very low processing time since the proposed quantizers are fixed, much less than the required time for the aforementioned methods that we compare with as well as much less than the time required for fractal image coding. In the end, the appropriate discussion is provided comparing the results with a scheme based on linear prediction and dual-mode quantization.

     

Advanced LMI based analysis and design for Acrobot walking

This article aims to further improve previously developed design for Acrobot walking based on partial exact feedback linearisation of order 3. Namely, such an exact system transformation leads to an almost linear system where error dynamics along trajectory to be tracked is a 4-dimensional linear time-varying system having three time-varying entries only, the remaining entries being either zero or one. In such a way, exponentially stable tracking can be obtained by quadratically stabilising a linear system with polytopic uncertainty. The current improvement is based on applying linear matrix inequalities (LMI) methods to solve this problem numerically. This careful analysis significantly improves previously known approaches. Numerical simulations of Acrobot walking based on the above-mentioned LMI design are demonstrated as well.     

Fostering scholarly productivity through academic and internship research training environments.

How can training programs foster counseling and clinical psychologists' scholarly productivity? This study examined the impact of academic and internship research training environments (RTEs) on the scholarly activity of 223 early career professionals. Results supported the construct validity of the Internship Research Training Environment scale through cross-validation and confirmatory factor analysis. Findings revealed differences in perceptions of the internship RTE and scholarly productivity as a function of academic training philosophy and internship training philosophy. Finally, results suggested that academic and internship RTEs could influence research interest and scholarly productivity indirectly by enhancing research self-efficacy and research outcome expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testosterone has rewarding affective properties in male rats: Implications for the biological basis of sexual motivation.

Evidence from mammalian species, including humans, suggests that testosterone (TST) enhances motivational aspects of sexual behavior, although the mechanism by which TST exerts this effect is unknown. The hypothesis that increases in plasma TST have rewarding affective properties was examined. Acute elevations of plasma TST were induced in intact male rats by systemic administration of a recently developed testosterone-hydroxypropyl-β-cyclodextrin inclusion complex that mimics pulsatile release of the hormone. In a conditioned-place-preference paradigm, rats displayed a preference for an environment previously paired with TST administration (800 μg/kg and 1,200 μg/kg) as opposed to an environment paired with saline administration, indicating that TST has rewarding affective properties. The findings suggest that TST may enhance motivational aspects of mammalian sexual behavior by facilitating acquisition or expression of learned associations between environmental stimuli and sexual activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to: “SPOCU”: scaled polynomial constant unit activation function

Neural Computing and Applications - Addendum on SPOCU fitting and Erratum.     

Longitudinal associations between hostility in adolescents' family relationships and friendships and hostility in their romantic relationships.

This study examined longitudinal predictors of hostility in adolescents' romantic relationships. The sample included 110 adolescents and their parents from 72 families. Observational measures of parents' marital hostility and parent-child hostility and self-reports of hostility in close friendships were collected when adolescents ranged from 14 to 16 years old. Three years later, when they were 17 to 19 years old, adolescents reported on the hostility in their romantic relationships. Results indicated that hostility in parents' marital relationships and in adolescents' friendships accounted for independent variance in hostility in adolescents' later romantic relationships. Results highlight the importance of both family relationships and friendships for predicting hostility in adolescents' romantic relationships over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental investigation and theoretical modeling of dehydriding process in high-pressure metal hydride hydrogen storage systems

This study explores the endothermic dehydriding (desorption) reaction that takes place in a high-pressure metal hydride (HPMH) hydrogen storage system when hydrogen gas is released to the fuel cell. The reaction is sustained by circulating warm fluid through a heat exchanger embedded in the HPMH powder. A systematic approach to modeling the dehydriding process is presented, which is validated against experimental data using two drastically different heat exchangers, one using a modular tube-fin design and the other a simpler coiled-tube design. Experiments were performed inside a 101.6-mm (4-in) diameter pressure vessel to investigate the influences of hydrogen release rate, heat exchanger fluid flow rate and fluid temperature on the dehydriding process for the HPMH Ti_1.1CrMn. It is shown the dehydriding reaction rate can be accelerated by increasing the fluid temperature and/or the rate of pressure drop. HPMH particles located in warmer locations close to heat exchanger surfaces both began and finished dehydriding earlier than particles farther away. 2-D and 3-D models were created in Fluent to assess the dehydriding performances of the modular tube-fin heat exchanger and coiled-tube heat exchanger, respectively. The models are shown to be quite accurate at predicting the spatial and temporal variations of metal hydride temperature during the dehydriding reaction.     

Creating trauma-informed systems: Child welfare, education, first responders, health care, juvenile justice.

Children and adolescents who are exposed to traumatic events are helped by numerous child-serving agencies, including health, mental health, education, child welfare, first responder, and criminal justice systems to assist them in their recovery. Service providers need to incorporate a trauma-informed perspective in their practices to enhance the quality of care for these children. This includes making sure that children and adolescents are screened for trauma exposure; that service providers use evidence-informed practices; that resources on trauma are available to providers, survivors, and their families; and that there is a continuity of care across service systems. This article reviews how traumatic stress impacts children and adolescents' daily functioning and how various service systems approach trauma services differently. It also provides recommendations for how to make each of these service systems more trauma informed and an appendix detailing resources in the National Child Traumatic Stress Network that have been produced to meet this objective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case of using the Semantic Interoperability Framework for custom orthopedic implants manufacturing

The efficiency and effectiveness of the daily practice in orthopedic surgery depend on the availability, interoperability and unique access to a wide set of information, related to the patient’s medical record and diagnosis, domain knowledge and available resources and staff. The most important of the tangible resources, needed for the therapeutic or preventive actions are orthopedic implants. In some cases, the implants may be highly complex and customized products, which need to be manufactured (assembled) on basis of the above information in a shortest possible timeframe. In this paper, the case of the custom orthopedic implants manufacturing is described from the perspective of the collaborative enterprising, with special consideration of the interoperability issues of the involved enterprise collaboration. It is shown how the previously developed Semantic Interoperability Framework can be used to improve the efficiency of the manufacturing and other relevant processes.