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961.
To unlock the full potential of evolution in digital media, a Tierra-like system using network-type assembly-like language
has been constructed. In the system, like Avida, digital creatures, self-replicating programs, live in a discrete 2D torus
space and an interaction between creatures is restricted locally. Bearing a genetic network in mind, network structure is
introduced. In the previous works, it is shown that the possibility that the network-type model has more potential of evolution
than a linear-type model like Avida in a simple environment. In this paper, to study the potential of evolution more precisely,
we model the effects of environment other than creatures. As one of the simplest models of such environment, the cost of execution,
i.e. executing time, is introduced. The difficult environment to live in costs high to execute instructions, the easy environment
does low. In computer experiments, we have investigated the influence of change in environment by analyzing the process of
evolution and diversity of the system. Experimental results show that the network-type system keeps more stable diversity
than the linear-type system does, even when the environment changes drastically. This indicates the possibility that the network-type
system has more potential of evolution than the linear-type system has.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
962.
We constructed a probabilistic simulator that allows all the events in population dynamics such as death, birth, mutation,
and suppression/stimulation to be described by probabilistic rules. The simulator also facilitates a lattice used for expressing
distribution and diversity (number of distinct strains) of quasispecies. The simulator is used to investigate the diversity
threshold in HIV and T-cell interaction.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
963.
964.
Zusammenfassung Für Krankenh?user sind Anwendungen für kooperativ angelegte Behandlungsprozesse wesentliche Werkzeuge um einen zeitnahen einrichtungs-
und sektorübergreifenden Austausch patientenbezogener medizinischer Daten zu gew?hrleisten. 相似文献
965.
Which signals are important in gaining attention in science? For a group of 1,371 scientific articles published in 17 demography
journals in the years 1990-1992 we track their influence and discern which signals are important in receiving citations. Three
types of signals are examined: the author's reputation (as producer of the idea), the journal (as the broker of the idea),
and the state of uncitedness (as an indication of the assessment by the scientific community of an idea). The empirical analysis
points out that, first, the reputation of journals plays an overriding role in gaining attention in science. Second, in contrast
to common wisdom, the state of uncitedness does not affect the future probability of being cited. And third, the reputation
of a journal may help to get late recognition (so-called sleeping beauties) as well as generate 'flash-in-the-pans': immediately
noted articles but apparently not very influential in the long run. 相似文献
966.
数字版权保护技术已经成为网络电视中除了视频编码技术以外的又一项核心技术。它用于保护内容所有人的版权,控制客户对于内容的使用。文章在阐述OMADRM标准的基础上,提出了一种适应国内广电系统实际播控环境的TS制式节目的DRM解决方案,并根据自行开发的演示系统,就其加密效率加以论证。 相似文献
967.
José Luis Montañez-Soto Salvador Alegret Juan Alfredo Salazar-Montoya Emma Gloria Ramos-Ramírez 《European Food Research and Technology》2006,223(3):379-386
In this work a novel amperometric biosensor for fructose determination in solutions was developed. The device was constructed by the incorporation of a tetrathiofulvalene-tetracyanoquinodimethane organic conducting salt and fructose dehydrogenase enzyme, include in a polymeric matrix of epoxy resin and graphite powder. Because of the electrocatalytic function of the salt, the direct transfer of the electron between the reduced prosthetic group (PQQH2) of the enzyme and the transducing material, was verified at a low working potential (150 mV vs. Ag/AgCl), where the interfering reactions were minimized. The response time at 90% of the steady state value was less than 20 s. The current response was directly proportional to the D-fructose concentration from 0.01 to 0.3 mmol/l with a detection limit of 0.005 mmol/l (signal/noise of 3) and a sensitivity of 1.9985 μA/mmol. The biosensor sensitivity diminishes when its surface is not polished between successive determinations, and remains constant (rsd=1.85, n=10) when the surface is polished between determinations. The effects of temperature and pH on the biosensor response were studied and analyzed; also the properties of the enzyme (Km
ap, I
max, Q10) were determinate in this work. The biosensor was used to determine fructose in high fructose syrups and there were not significant differences between these results and those obtained by HPLC (p≤0.05). During 4 months, in intermittent determinations the biosensor kept 100% of its original sensitivity and after 18 months stored at 4°C, it only lost 32% of its sensitivity. The simplicity, low working potential, high stability and good performance of this biosensor shows a great potential for its use in the fructose determination. 相似文献
968.
969.
Chun Lin Ma Qing Feng Wang Rufen Zhang Jikun Li 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(2):229-235
Six triorganotin(IV) complexes of the type {(R3Sn)2[C3S3(COO)2]}n (R = C6H5 1; n-Bu 2; PhCH2 4; p-F-PhCH2 5; o-F-PhCH2 6) and {(R3Sn)2[C3S3(COO)2]}n·[EtOH] (R = Me 3) have been synthesized by the reaction of bis(carboxymethyl)trithiocarbonate with triorganotin(IV) chloride
in the presence of sodium ethoxide. All complexes were characterized by elemental analysis IR, 1H, 13C and 119Sn NMR spectroscopy. Except for 4–6, all complexes were also characterized by X-ray crystallography. The X-ray date revealed
that complexes 1–3 show two-dimensional network polymeric structure in which the geometries of tin atoms are trigonal bipyramid
with the axial positions occupied by carboxylic oxygen atoms. 相似文献
970.
The conversion of heavy paraffin and aromatics into a high-quality diesel fraction was performed in a microplant using a WNiPd/CeY-alumina catalyst. The effects of aromatics and naphtheno-aromatics on mild hydrocracking of hexadecane were studied at different concentrations. Two catalysts, with and without Pd and thermal treatment, were characterized by FTIR, XPS, and TPD of ammonia and ammonia plus naphthalene to complement previous study about the surface composition. The hydrocracking activity and selectivity were tested using different amounts and types of aromatics. This study demonstrated the presence of two acid strengths that contribute in different ways to paraffin and aromatics isomerization, ring opening, and cracking reactions. The product distribution obtained by mild hydrocracking of n-C16 is between amorphous (SiO2Al2O3) and Y-zeolite type of support. The aromatic adsorption on acid sites reduces the cracking rate and improves the survival of di- and tri-branched paraffin. A model for the path of reaction is discussed to explain the results. 相似文献