Design and Analysis of Transport Protocols for Reliable High-Speed Communications

The design and analysis of transport protocols for reliable communications constitutes the topic of this dissertation. These transport protocols guarantee the sequenced and complete delivery of user data over networks which may lose, duplicate and reorder packets. Reliable transport services are required by a wide range of applications such as the World-Wide Web, remote network access, and distributed computing. The design of these protocols is heavily influenced by the parameters of the underlying network infrastructure and by the assumptions about the host computers and applications. Therefore the recent advances in optical transmission and computer technologies stimulated the design of several novel transport protocols. Many of the proposed protocols use similar or at least related techniques. Our goal with this thesis is to improve the understanding of reliable communications by analyzing the protocols that implement this service and to contribute to the design of reliable transport protocols. The basis of our analysis is the formal specification and verification of the protocol mechanisms under investigation. The behavior of the protocol is captured by a state-transition system and properties are established using assertional reasoning. The framework is capable to handle unbounded and modulo-N state variables and to capture real-time aspects of the protocols which is essential for the modeling of realistic systems. Practical protocols of considerable complexity are specified and verified in the thesis. One advantage of the formal verification is that it increases our confidence in the correctness of these protocols. The formalism forces us to clarify all the details of the working of the protocol and to state explicitly every assumption about the protocol and its environment. During the process of the verification one also gains insight into the mechanisms of the protocol. But probably the most important result is that during the verication we obtain conditions for the correctness of the protocol in the form of inequalities on some protocol parameters. These conditions allow the comparison of the different protocol mechanisms and can be used to judge the suitability of a protocol for a certain environment. The functionality of transport protocols can be naturally divided into data transfer and connection management. Data transfer deals with the sequenced delivery of user data, while connection management is concerned with the orderly setup and release of connections.\ud In the thesis we study three different data transfer protocols. The usage of timestamps in data transfer protocols is analyzed in detail through the example of the PAWS mechanism which was proposed as an extension to TCP. The analysis reveals that the use of timestamps increases the functionality of the transport protocol by facilitating the simple measurement of round-trip delays, but it also reduces the maximum allowable transmission rate as compared to the plain sliding-window protocol. Another data transfer protocol called SNR is analyzed which is based on the idea of periodic state exchange. We start from an earlier specification of SNR and compare it to the plain sliding-window protocol. The analysis reveals that the maximum transmission speed achievable by that SNR specification is higher than that of the plain sliding-window protocol, but it comes with a serious limitation. In the SNR specication it is assumed that no duplicates are generated by either the network or the transport protocol itself. This assumption may seriously limit the eective performance of the protocol in case of losses in the network and demonstrates the importance of considering all the assumptions when selecting a protocol for a certain environment. The use of timestamps is also investigated in the context of connection management protocols. The detailed analysis of the connection setup protocol SCMP is presented which is based on the assumption that clocks of computers can be synchronized relatively cheaply even in a large network. In our verification it is proven that the safety of the protocol does not depend of the synchronization assumption, therefore the protocol can be used safely in cases when there are no absolute guarantees of the clocks being synchronized. Since practical clock synchronization algorithms give only probabilistic guarantees, our result provides an important theoretical support of the applicability of the protocol in practical environments. Based on earlier work by others, a family of connection management protocols is analyzed that use a cache to store information needed to shorten the connection setup latency. We contribute to this work by proposing improvements which allow to reduce considerably the memory usage of these protocols. Furthermore, we show that the correctness of the protocol can be assured without assuming an upper bound on the incarnation lifetime, i.e., the maximum duration of a connection. This result greatly improves the practical applicability of the protocol

Hexapod Design For All-Sky Sidereal Tracking

In this paper we describe a hexapod-based telescope mount system intended to provide sidereal tracking for the Fly's Eye Camera project -- an upcoming moderate, 21"/pixel resolution all-sky survey. By exploiting such a kind of meter-sized telescope mount, we get a device which is both capable of compensating for the apparent rotation of the celestial sphere and the same design can be used independently from the actual geographical location. Our construction is the sole currently operating hexapod telescope mount performing dedicated optical imaging survey with a sub-arcsecond tracking precision.Comment: Accepted for publication in PASP, 10 page

Transglutaminase 2 Has Metabolic and Vascular Regulatory Functions Revealed by In Vivo Activation of Alpha1-Adrenergic Receptor

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The Fly's Eye Camera System -- an instrument design for large \'etendue time-domain survey

In this paper we briefly summarize the design concepts of the Fly's Eye Camera System, a proposed high resolution all-sky monitoring device which intends to perform high cadence time domain astronomy in multiple optical passbands while still accomplish a high \'etendue. Fundings have already been accepted by the Hungarian Academy of Sciences in order to design and build a Fly's Eye device unit. Beyond the technical details and the actual scientific goals, this paper also discusses the possibilities and yields of a network operation involving ~10 sites distributed geographically in a nearly homogeneous manner. Currently, we expect to finalize the mount assembly -- that performs the sidereal tracking during the exposures -- until the end of 2012 and to have a working prototype with a reduced number of individual cameras sometimes in the spring or summer of 2013.Comment: Accepted for publication in AN, 4.05 pages. Website of the project: http://flyseye.net

Evolution of integrated open aquaculture systems in Hungary: results from a case study

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Neutron kölcsönhatások kísérleti és elméleti vizsgálata = Experimental and theoretical studies on neutron interactions

1) Több mint 20 neutron indukált magreakció gerjesztési függvényének pontosítása új adatok mérésével és elméleti modell (STAPRE, EMPIRE 2.19) számításokkal a 0-22 MeV energiatartományban, az IAEA Reference Neutron Activation Library kiegészítésére, az EC OECD- NEA WPEC keretében az európai fúziós reaktor tervezéséhez és az IRDF-2002 új dozimetriai könyvtár ellenőrzésére (Geel,IRMM-Debrecen; Debrecen-Jülich, KFA-Kairó). 2) A 27Al(n,p)27Mg reakció gerjesztési függvényének analízisével új neutron energia monitor ajánlása a 13-15 MeV tartományra analitikus formában: s(En) = (-12.654En + 254.117) mb, ami a 27Mg aktivitásának mérésével, a spektrumra átlagolt ismeretében lehetővé teszi a D+T plazmából származó neutronok hozamának meghatározását is (Debrecen-Obninsk). 3) A Zn, Pt, Ir és Cd céltárgyakon létrehozott (p,x) és (d,x) reakciókban 61 gerjesztési függvény mérése és számítása az ALICE-IPPE modellel a küszöb- 80 MeV tartományban, amelyek zömére korábban nem volt adat (Brüsszel-Debrecen-Sendai, CYRIC-Obninsk). 4) A NAÜ által koordinált program keretében plasztik töltésű taposóaknák észlelésére és beazonosítására neutronokra alapozott módszerek és hordozható eszközök kifejlesztése. 5) Az epitermikus neutronok lelassulásán alapuló új módszer kidolgozása kiterjedt közegek hidrogéntartalmának meghatározásra. A relatív fluxus és a hidrogénatomok száma közötti kapcsolat analitikus leírása (Debrecen-Tsukuba, KEK, Japán; Debrecen-Kairó-Tsukuba). 6) Eljárás kidolgozása az átlagos aktiváló termikus és epitermikus neutron fluxus kísérleti meghatározására kiterjedt, erősen abszorbeáló közegekre is (Debrecen-Tsukuba). | 1) More than 20 precise excitation functions of neutron induced reactions were given by new data and model calculations (STAPRE, EMOIRE 2.19) in the 0-22 MeV range to complete the IAEA Reference Neutron Activation Library, to design the European fusion reactor in collaboration with the EC OECD-NEA WPEC and for the validation of IRDF-2002 new dosimetry library (Geel,IRMM-Debrecen; Debrecen-Jülich, KFA-Cairo). 2) Using the evaluated excitation function for 27Al(n,p)27Mg reaction a new energy monitor was given for the 13-15 MeV interval: s(En) = (-12.654En + 254.117) mb. In the knowledge of the spectrum averaged data the yield of D+T plasma neutrons can also be determined by the measurement of 27Mg activity (Debrecen-Obninsk). 3) Measurements and calculations(ALICE-IPPE) of 61 excitation functions from threshold to 80 MeV produced in (p,x) and (d,x) reactions on Zn, Pt, Ir and Cd targets. Most of these data were determined for the first time (Brussels-Debrecen-Sendai, CYRIC-Obninsk). 4) Development of neutron based methods and hand-held probes for the detection and identification of plastic anti-personnel landmines in cooperation with the IAEA. 5) Development of a new method for bulk hydrogen analysis using epithermal neutrons. Description the relation between the relative flux and the number of hydrogen atoms by analytical expression (Debrecen-Tsukuba, KEK, Japan; Debrecen-Cairo-Tsukuba). 6) An experimental procedure was elaborated for the determination of the average activating flux of thermal and epithermal neutrons in bulky samples containing highly absorbing elements (Debrecen-Tsukuba)

Browning deficiency and low mobilization of fatty acids in gonadal white adipose tissue leads to decreased cold-tolerance of transglutaminase 2 knock-out mice

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Resiniferatoxin mediated ablation of TRPV1+ neurons removes TRPA1 as well

Resiniferatoxin, the most potent agonist of inflammatory pain/vanilloid receptor/cation channel (TRPV1) can be used for neuron subtype specific ablation of pain generating cells at the level of the peripheral nervous system by Ca(2+)-excytotoxicity. Molecular neurosurgery is an emerging technology either to alleviate severe pain in cancer or treat/prevent different local neuropathies. Our aim was determining sensory modalities that may be lost after resiniferatoxin treatment.status: publishe

Effect of Carotenoids, Oligosaccharides and Anthocyanins on Growth Performance, Immunological Parameters and Intestinal Morphology in Broiler Chickens Challenged with Escherichia coli Lipopolysaccharide

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Telemetriás és online nontelemetriás adatok elemzése szívelégtelen betegek fizikai aktivitásának jellemzésére | Analysis of telemetry, on-line and non-telemetry data for characterization of the physical activity of patients with heart failure

Absztrakt: Bevezetés: Több kutatás kimutatta, hogy a szívelégtelenség prevalenciája a nyugati országokban 0,4–2% közötti értékre tehető. Célkitűzés: Tanulmányunk célja annak meghatározása volt, hogy a szívelégtelenséggel élő betegeknél a telemetriás úton kapott fizikai aktivitás százalékos érték felhasználásával megbecsülhető-e a hatperces sétateszt során megtett távolság. Módszer: A kutatásba 17, szívelégtelenségben szenvedő beteget vontunk be (n = 17; életkor 57,35 év ± 9,54; testtömeg 98,71 kg ± 9,89; átlag-BMI 36,69 ± 3,67). A fizikai aktivitást jellemző két adatsor felhasználásával lineáris regressziót végeztünk, amelynek során egy matematikai egyenletet kaptunk, így a fizikai aktivitás százalékérték segítségével becsülhető a hatperces sétateszt során megtett távolság. Eredmények: A kapott adataink további elemzése során arra a következtetésre jutottunk, hogy e betegeknél a CRT-készülékből származó adatok közül a PA% segítségével becsülhetővé válik a hatperces séta alatt megtett távolság, amely e betegek terhelhetőségének egyik jellemző információja lehet. Következtetések: Módszerünk felhasználásával a betegek állapotváltozása az implantált elektronikus eszközzel telemetriásan folyamatosan követhető. Orv Hetil. 2017; 158(35): 1390–1395. | Abstract: Introduction: Several studies have demonstrated that the prevalence of heart disease can be accounted for between 0.4 and 2% in developed countries. Aim: The present study aimed to use the PA% of the telemetry data to estimate the 6-minute walk test result. Method: A total of seventeen patients with heart disease; 3 females and 14 males; age: 57.35 yrs ± 9.54; body mass 98.71 ± 9.89 kg; average BMI 36.69 ± 3.67 were recruited into the study. Using the two sets of values describing physical performance, linear regression was calculated providing a mathematical equation, thus, the Physical Activity % value is used to estimate the distance traveled over a 6-minute walk test. Results: On further data analysis, we have come to the conclusion that the distance walked during the six-minute-long test may be measured by PA% from the data of CRT device. Conclusions: With our method, based on the values received from the physical activity sensor implanted into the resynchronisation devices, changes in patients’ health status could be monitored telemetrically with the assistance from the implanted electronic device. Orv Hetil. 2017; 158(35): 1390–1395