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Intermedia Synchronization Protocol for Continuous Media Using MPEG-4 in Mobile Distributed Systems
( Eduardo Lopez Dominguez ),( Saul E. Pomares Hernandez ),( Pilar Gomez Gil ),( Jorge De La Calleja ),( Antonio Benitez ),( Antonio Marin-hernandez ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.6
The preservation of temporal dependencies among a group of processes that exchange continuous media at runtime is a key issue for emerging mobile distributed systems (MDS), such as monitoring of biosignals and interactive multiuser games. Although several works are oriented to satisfy temporal dependencies, most of them are not suitable for MDSs. In general, an MDS is characterized by the absence of global references (e.g. shared memory and wall clock), host mobility, limited processing and storage capabilities in mobile hosts, and limited bandwidth on wireless communication channels. This paper proposes an asymmetric synchronization protocol to be used at runtime in an MDS without using a common reference. One main aspect of our synchronization protocol is that it translates temporal constraints to causal dependencies of the continuous media data as seen by the mobile hosts. We simulate the protocol by considering a cellular network environment and by using MPEG-4 encoders. The simulation results show that our protocol is effective in reducing the synchronization error. In addition, the protocol is efficient in terms of processing and storage costs at the mobile devices, as well as in the overhead attached per message across the wired and wireless channels.
Electrochemical Study of Three Stainless Steel Alloys and Titanium Metal in Cola Soft Drinks
Peralta-Lopez, D.,Sotelo-Mazon, O.,Henao, J.,Porcayo-Calderon, J.,Valdez, S.,Salinas-Solano, G.,Martinez-Gomez, L. The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.4
Stainless steels and titanium alloys are widely used in the medical industry as replacement materials. These materials may be affected by the conditions and type of environment. In the same manner, soft drinks are widely consumed products. It is of interest for dental industry to know the behavior of medical-grade alloys when these are in contact with soft drinks, since any excessive ion release can suppose a risk for human health. In the present study, the electrochemical behavior of three stainless steel alloys and pure titanium was analyzed using three types of cola soft drinks as electrolyte. The objective of this study was to evaluate the response of these metallic materials in each type of solution (cola standard, light and zero). Different electrochemical techniques were used for the evaluation of the alloys, namely potentiodynamic polarization, linear polarization, and open-circuit potential measurements. The corrosion resistance of the stainless-steel alloys and titanium in the cola soft drinks was provided by the formation of a stable passive film formed by metal oxides. Scanning electron microscopy was used as a complementary technique to reveal corrosion phenomena at the surface of the materials evaluated.
Griselda I. Zamora-Gomez,Arturo Zavala-Rio,Daniela J. Lopez-Araujo,Victor Santibanz 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
Global continuous control for the finite-time or (local) exponential stabilization of mechanical systems with bounded inputs is achieved involving desired conservative-force compensation. With respect to the on-line compensation case, the proposed controller entails a closed-loop analysis with considerably higher degree of complexity, whence more involved requirements prove to arise. Other important analytical limitations are further overcome through the developed algorithm. Numerical simulations considering a robotic arm model corroborate the efficiency of the proposed scheme.
Assembly strategies of wind turbine towers for minimum fatigue damage
Cristina Nunez-Casado,Oscar Lopez-Garcia,Enrique Gomez de las Heras,Alvaro Cuerva-Tejero,Cristobal Gallego-Castillo 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6
The aim of this paper is to present a method to obtain the dynamic response of a wind turbine tower in time domain by means of the generation of time series and to estimate the associated fatigue damage by means of a Rainflow counting algorithm. The proposed method is based on assuming the vortex shedding is a bidimensional phenomena and on following a classical modal superposition method to obtain the structure dynamic response. Four different wind turbine tower geometric configurations have been analyzed in a range of usual wind velocities and covering extreme wind velocities. The obtained results have shown that, depending on the turbulence intensity and the mean wind velocity, there are tower geometric configurations more advantageous from the fatigue load standpoint. Consequently, the presented model can be utilized to define assembly strategies oriented to fatigue damage minimization.
Pedro Melendez,Veronica Gomez,Hans Bothe,Francisco Rodriguez,Juan Velez,Hernando Lopez,Julian Bartolome,Louis Archbald 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.3
The objective of this study was to compare ovulation rate, number of large ovarian follicles, and concentrations of plasma progesterone (P4) and non-esterified fatty acids (NEFA) between lame (n = 10) and non-lame (n = 10) lactating Holstein cows. The study was conducted in an organic dairy farm, and cows were evaluated by undertaking ultrasonography and blood sampling every 3 days from 30 days postpartum for a period of 34 days. Cows which became lame during the first 30 days postpartum experienced a lower ovulation rate determined by the presence of a corpus luteum (50% presence for lame cows and 100% for non-lame cows, p ≤ 0.05). The number of large ovarian follicles in the ovaries was 5 for lame cows and 7 for non-lame cows (p = 0.09). Compared to non-lame cows, lame cows had significantly lower (p ≤ 0.05) concentrations of plasma P4. Furthermore, NEFA concentrations were lower (p ≤ 0.05) in lame cows than in non-lame cows. It is concluded that lameness in postpartum dairy cows is associated with ovulation failure and lower concentrations of P4 and NEFA.
Cruz-Silva, Rodolfo,Morelos-Gomez, Aaron,Kim, Hyung-ick,Jang, Hong-kyu,Tristan, Ferdinando,Vega-Diaz, Sofia,Rajukumar, Lakshmy P.,Elí,as, Ana Laura,Perea-Lopez, Nestor,Suhr, Jonghwan,Endo, Morin American Chemical Society 2014 ACS NANO Vol.8 No.6
<P>Graphene oxide (GO) has recently become an attractive building block for fabricating graphene-based functional materials. GO films and fibers have been prepared mainly by vacuum filtration and wet spinning. These materials exhibit relatively high Young’s moduli but low toughness and a high tendency to tear or break. Here, we report an alternative method, using bar coating and drying of water/GO dispersions, for preparing large-area GO thin films (<I>e.g.</I>, 800–1200 cm<SUP>2</SUP> or larger) with an outstanding mechanical behavior and excellent tear resistance. These dried films were subsequently scrolled to prepare GO fibers with extremely large elongation to fracture (up to 76%), high toughness (up to 17 J/m<SUP>3</SUP>), and attractive macroscopic properties, such as uniform circular cross section, smooth surface, and great knotability. This method is simple, and after thermal reduction of the GO material, it can render highly electrically conducting graphene-based fibers with values up to 416 S/cm at room temperature. In this context, GO fibers annealed at 2000 °C were also successfully used as electron field emitters operating at low turn on voltages of <I>ca.</I> 0.48 V/μm and high current densities (5.3 A/cm<SUP>2</SUP>). Robust GO fibers and large-area films with fascinating architectures and outstanding mechanical and electrical properties were prepared with bar coating followed by dry film scrolling.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-6/nn501098d/production/images/medium/nn-2014-01098d_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn501098d'>ACS Electronic Supporting Info</A></P>