Bandwidth reduction for remote navigation systems through view prediction and progressive transmission

Remote navigation systems, such as exploration of virtual 3D worlds or remote surgery, usually require higher bandwidth than the Internet connection commonly available at home. In this paper, we explore a set of techniques to reduce the bandwidth required by these applications. Our system consists of a client PC equipped with a graphics card, and a remote high-end server. The server hosts the remote environment and does the actual rendering of the scenes for several clients, and the new image is passed to them. This scheme is suitable when the data has a copyright or when its size may exceed the rendering capabilities of the client. The general scheme is the following: each time the position changes, the new view is predicted by both the client and the server and the difference information between the predicted view and the correct one is sent to the client. To reduce bandwidth we can improve the prediction method, and the transmission system. We present here two groups of techniques: First, a set of lossless methods which achieve reductions of up to a 9:1 ratio. These are a combination of a two-level forward warping, that takes advantage of spatial coherence, and a masking method, which allows to transmit only the information that really needs to be updated. Second, a set of lossy methods suitable for very low bandwidth environments which involve both progressive transmission and image reuse. They consider relevant parameters such as the number of pixels, the amount of information they provide, and their colour deviation in order to create a strategy for prioritizing the information transmission. This system allows to improve up to an additional 4:1 ratio. The quality of the generated images is very high, and often indistinguishable from the correct ones.     

A new blocking problem from Java-based schedulers

We consider a form of blocking, which is typical in client–server systems including those implemented under the Enterprise JavaBean (EJB) specification. The novel feature is that tasks must wait for one of a number of parallel queues to clear its outstanding work. Thus, blocking time is the minimum of sojourn times at the parallel queues. Under certain simplifying assumptions, we solve this model for the probability distribution of blocking time and obtain a simple formula for its mean value. We then use this result in an aggregate server model of a larger queueing network in which further non-standard techniques are included to represent this form of blocking. We compare our approximate results against simulation data, obtaining good agreement for both system throughput and queue length probability distributions at equilibrium.     

New Insights in the Use of Trehalose and Modified Starches for the Encapsulation of Orange Essential Oil

During the encapsulation of aromas by spray-drying, some volatile components may be lost; consequently, the sensory profile could be modified in the final product. Therefore, the selection of the carrier matrix for the encapsulation is crucial to obtain high aroma retention and long shelf-life stability, reduce aroma oxidation and increase physical stability of the powder. With the aim of studying the use of trehalose for the encapsulation of orange essential oil, emulsions were prepared containing mixtures of trehalose–maltodextrin (TMD) and sucrose–maltodextrin (SMD). Two modified starches were used as emulsifiers. The emulsions were spray-dried and stored at 25 and 37 °C. The aroma retention was evaluated using head space–solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC-MS) and by sensory evaluation. In addition, some physical properties of orange essential oil powders, such as water sorption and glass transition temperature (T _g), were determined. The sensory profiles obtained for TMD and SMD were different: TMD formulations retained mainly limonene, while SMD retained mostly α-pinene and myrcene. The modified starches (Capsul and Hi Cap) used as emulsifiers also affected the retention of certain volatiles. Therefore, the selection of components in the carrier matrix is relevant to the retention of aromas in orange oil powders. Regarding the physical properties, TMD formulations presented better characteristics in comparison to SMD, particularly due to the higher T _g values. The high aroma retention levels and the good physical characteristics are promising results in relation to the inclusion of the developed formulations in dehydrated citric juices.     

Regulation of food advertising on television for the prevention of childhood obesity

Obesity is a serious global epidemic and the prevention strategies implemented have been insufficient. Numerous environmental factors have been associated with risk of obesity and their full consideration in prevention policies is important. The connection between food advertising on television and childhood obesity has been demonstrated. The large number of advertisements for unhealthy foods targeted at children through television and its possible impact on health has led some countries to legislate on this matter. However, a conceptual framework of reference enabling legislation must be internationally defined in order to achieve a real impact in preventing childhood obesity. This paper reviews scientific evidence on the relationship between food advertising and childhood obesity as a basis for developing public policies to regulate food marketing on television.     

Electrochemical synthesis and characterization of new electrodes based on poly‐hematoxylin films

The poly‐hematoxylin films undoped (p‐HX) and doped with strontium (p‐HX‐Sr) were prepared on the platinum electrodes (Pt) using cyclic voltammetry. The influence of experimental parameters, such as: anodic potential and number of voltammetric cycles on the films synthesis was investigated by electrochemical impedance spectroscopy (EIS). The results showed that, the optimal conditions to obtain the poly‐hematoxylin films on platinum electrode from 10^?2 mol L^?1 NaNO₃ solution, were found by recording 10 voltammetric cycles at an anodic potential of 1.5 V. Electrocatalytic activity of the poly‐hematoxylin‐platinum (p‐HX/Pt) and poly‐hematoxylin‐strontium‐platinum (p‐HX‐Sr/Pt) electrodes was tested for electrochemical degradation of benzocaine using UV‐Vis spectrophotometry. Both, the mechanisms of hematoxylin (HX) polymerization, as well as benzocaine degradation were proposed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of two compatibilizers on clay/PP nanocomposites properties

This article investigates the influence on mechanical properties of using a two compatibilizer system. Cloisite‐Na Clay (ClNa) was organically modified in different ways with a polyethermonoamine and maleated polypropylene (MA‐g‐PP) added as a second compatibilizer. A corotating twin‐screw extruder was used to obtain nanocomposites based on polypropylene via the melt intercalation technique. X‐ray diffraction and differential scanning calorimetric results showed that intercalated nanocomposites with improved thermal stability were obtained. Increases of 8% in tensile strength, 34% in modulus, and 20% in crystallinity were observed. Also an increase of 23% in creep properties was observed when using these two compatibilizer system and 1% clay. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Helping child flood victims using group EMDR intervention in Argentina: Treatment outcome and gender differences.

A comprehensive group intervention with 124 children who experienced disaster-related trauma during a massive flood in Santa Fe, Argentina, in 2003 is illustrated, utilizing a one-session group eye movement desensitization and reprocessing (EMDR) protocol. A posttreatment session was done 3 months after the treatment intervention to evaluate results. Results of this one-session treatment procedure, utilizing the EMDR-Integrative Group Treatment Protocol, showed statistically significant reduction of symptoms immediately after the intervention. These statistically significant differences were sustained at posttreatment evaluation 3 months later, as measured by psychometric scales, and by clinical and behavioral observation. Data analysis also revealed significant gender differences. Despite methodological limitations, this study supports the efficacy of EMDR group treatment in the amelioration and prevention of posttraumatic stress disorder symptoms, providing an efficient, simple, and economic (in terms of time and resources) tool for disaster-related trauma. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chromium (III) uptake by agro-waste biosorbents: Chemical characterization, sorption–desorption studies, and mechanism

Within their complex structure, agro-waste materials such as sorghum straw (SS), oats straw (OS) and agave bagasse (AB) have functional groups (i.e. carboxyl and phenolic) that play a major role in metals sorption. The advantages of these materials include availability, low-cost, and a reasonable metal sorption capacity. These agro-waste materials were chemically characterized by acid-base titrations and ATR-FTIR analyses in order to determine their functional groups, equilibrium constants, and surface charge distribution. Batch experiments were conducted at pH 3 and 4, at 25 °C and 35 °C to determine the biosorbents chromium (III) sorption capacity. Partially saturated biosorbents were desorbed with HNO₃, NaOH, and EDTA at different concentrations and temperatures (25 °C, 35 °C, and 55 °C). Finally, the chromium (III) sorption mechanism was discussed.Agro-waste materials functional groups are associated, in part, to carboxyl and hydroxyl groups: these oxygen-containing sites play an important role in the chromium (III) removal. The maximum chromium (III) sorption capacity was 6.96, 12.97, and 11.44 mg/g at pH 4 for acid-washed SS, OS, and AB, respectively. The chromium (III) sorption capacity decreased at pH 3 because H⁺ ions competed for the same functional groups. On the other hand, an increase in temperature enhanced both the biosorbents chromium (III) sorption capacity and their desorption by EDTA. The most probable chromium (III) sorption mechanisms were ion exchange and complexation.The agro-waste materials studied herein efficiently remove chromium (III) from aqueous solution and, most importantly, EDTA can efficiently desorb Cr (III) from agro-waste materials at 55 °C.     

Developing GIS Applications with Objects: A Design Patterns Approach

In this paper we present an object-oriented approach for designing GIS applications; it combines well known software engineering practices with the use of design patterns as a conceptual tool to cope with recurrent problems appearing in the GIS domain. Our approach allows the designer to decouple the conceptual definition of application objects from their spatial representation. In this way, GIS applications can evolve smoothly, because maintenance is achieved by focusing on different concerns at different times. We show that our approach is also useful to support spatial features in conventional applications built with object-oriented technology. The structure of this paper is as follows: We first introduce design patterns, an efficient strategy to record design experience; then we discuss the most common design problems a developer of GIS applications must face. The core of our method is then presented by explaining how the use of decorators helps in extending objects to incorporate spatial attributes and behavior. Next, we analyze some recurrent design problems in the GIS domain and present some new patterns addressing those problems. Some further work is finally discussed.