Performance issues in parallelized network protocols

The cloud, rack-scale computing, and multi-core are the basis for today's computing platforms. Their intrinsic parallelism is a challenge for programmers, specially in areas lacking the necessary economies of scale in application/ code reuse because of the small number of potential users and frequently changing code and data. In this paper, based on an on-going collaboration with several projects in astrophysics, we present Pydron, a system to parallelize and execute sequential Python code on a cloud, cluster, or multi-core infrastructure. While focused on scientific applications, the solution we propose is general and provides a competitive alternative to moving the development effort to application specific platforms. Pydron uses semi-automatic parallelization and can parallelize with an API of only two decorators. Pydron also supports the scheduling and run-time management of the parallel code, regardless of the target platform. First experiences with real astrophysics data pipelines indicate Pydron significantly simplifies development without sacrificing the performance gains of parallelism at the machine or cluster level.

Local area network and wide area network are different network protocols, small and medium enterprises due to the geographical distribution of discrete and interface diversity, leading to its needs to be compatible with different network protocols, it is difficult to use a single network protocol to realize network architecture, and due to the ipv4 address scarcity, making its application or maintenance cost greatly increased, based on this, this paper presents the design of multi-protocol network architecture based on point-to-point protocol and frame relay, and with the advantages of the router is compatible with a variety of interfaces and protocols to connect different network interfaces, the paper also gives the configuration of routing information protocol and static routing through local area network, the paper presents the core information of frame relay and point-to-point protocol among the routers, and the paper gives the realization of the network address translation in the end.

Atom lithography is a technique to structure layers of atoms during deposition, using interactions of near-resonant light fields with neutral atoms. The basic scheme uses a standing wave light field, aligned just above a substrate, while a beam of atoms impinges perpendicularly on the standing wave light field. The interaction of the light field and the atoms focuses the atoms towards the crests or troughs of the standing wave intensity, dependent on the tuning of the light field. The focused atoms are subsequently deposited on the substrate, resulting in an array of lines, whose periodicity is determined by the wavelength of the light field. The standing wave light field can therefore be seen as an array of lenses, focusing the atom beam into an array of lines. The first experiments on atom lithography were performed in the 1990s with sodium and chromium. In this thesis experiments with iron are described, which is a magnetic element and thus allows for the creation of magnetic nanostructures. To focus atom beams into structures using atom lithography, well-colimated atom beams are required. The most common technique to create collimated atom beams is transverse laser cooling, but iron has no closed optical transition suitable for laser cooling. Fortunately Smeets and Te Sligte found that even then atom lithography of iron is possible. If the standing wave light field is considered to be an array of lenses, the focusing of the atom beam on a single lens is determined by the local collimation of the atom beam at that position. This local collimation is determined by the geometry of the beam source and the distance of the beam source to the standing wave lens. Using a small beam source (e.g. 1 mm diameter) positioned far from the standing wave (e.g. 1 m), the geometrically collimated atom beam is suitable for atom lithography. Chapter 3 shows what the implications of geometric collimation are on the structure formation in atom lithography. The geometric effects that locally collimate the atom beam on the sample also introduce local offset angles of the atom beam with respect to the focusing light field. Structure formation has been observed with lines of up to 7 nm high on a background layer of 15 nm average height, over areas of up to 400 µm × 6 mm. This indicates that the offset angles can vary over an 8 mrad range, which is more than an order of magnitude larger than the local angle of collimation. The offset angle influence the local geometry of the deposited structures: an increasing offset angle decreases the local line height, increases the width and creates a skewness in the local line shape. The local geometry of the lines has been modelled with a Monte Carlo particle tracking model and the results were compared to experiments. It was found that the highest and narrowest lines suffer from significant broadening due to surface diffusion in experiments, limiting the achievable structure width of iron on SiOx samples to about 80 nm. We have also found that in atom lithography without laser cooling, each standing wave lens is effectively imaging the source geometry onto the substrate. We therefore propose using structured atom beam sources to image more complex patterns on sub-wavelength scales in a parallel way. The reason to use iron in atom lithography, is the option to create magnetic nanostructures. However, in previous experiments no clear magnetic signature of the atom lithographic structuring of iron was found. Therefore in Chapter 4 firstly the magnetic properties of unstructured layers of iron (Fe), nickel (Ni) and FexNi1-x are investigated. These layers are all ferromagnetic, but with a reduced magnetic moment compared to bulk values due to contaminations and crystal growth effects. As a reference for periodic atom lithography structures, periodic line structures are created with interference lithography in a polymer layer and onto these structures thin layers of FexNi1-x are shadow deposited, thereby creating a layer periodically modulated in both height and elemental composition. This periodic modulation in composition has been observed with SEM-EDX on sub-micron scales. The structures showed a clear magnetic anisotropy with an easy axis along the direction of the lines, in accordance with expectations. In Chapter 5, the magnetic properties of atom lithographic iron line structures are presented. Using MOKE microscopy, direct comparison of structured and unstructured parts of a sample is possible, which allows for the observation of clear magnetic signatures due to the atom lithographic structuring. In layers of an average thickness of about 15 nm, no anisotropy is induced by the line structures, while a magnetic easy axis along the direction of the lines is expected. The line structures introduce an isotropic increase in the coercivity of the layers, indicating that the line structures can be considered as isotropic corrugations instead of directional line structures. For layers of 30 nm average thickness and thus higher line structures, a clear magnetic anisotropy is observed for the highest line structures. This anisotropy can be seen as a magnetic easy axis along the direction of the lines, as expected for line structures. However, we also observe a sharp increase in coercivity for applied fields perpendicular to the lines. This phenomenon is intriguing and may be explained by a pinning of head-to-head domain walls along the direction of the lines. In Chapter 5, we also report on the first results of co-deposition of FexNi1-x, where the Fe is structured into lines using atom lithography, while the Ni is deposited uniformly, thereby creating an alloy of modulating composition. Magnetic analysis of these structures indicates that these structures are anisotropic, both the coercivity and the shape of domain walls is dependent on the angle of the applied field relative to the line structures. Finally in Chapter 6, we investigate the possibilities to focus a thermal beam of atoms into a single 100 nm spot using light fields, thereby creating a nanopencil suitable for deposition of nanostructures. A Monte Carlo particle tracking program was developed to model the all optical focusing or funneling of 10 µm sized atom beams to a 100 nm spot. This model included effects of initial beam divergence, magnetic substructure, laser cooling, and spontaneous as well as stimulated diffusion and it was applied to a number of promising light field configurations. The best results obtained for experimentally realistic settings are a beam focused to a full width at half maximum of FWHM = 0.55 µm in a blue detuned hollow beam where atoms are focused towards the dark center, or a FWHM = 0.31 µm in a red detuned axicon light field, where atoms are focused towards the maximum intensity at the heart line. However, in the latter case the focused beam has a flux only 25 times larger than the background flux, which is unpractical for applications. The limiting factors of all schemes are heating due to stimulated diffusion and the limited interaction time available for a thermal beam of atoms. A nanopencil could be possible if it were based on the focussing of a slow and / or monochromatic atom beam, but this would seriously complicate the practical application of such a device.

There is tremendous need in collaborative design today for the integration of heterogeneous CAx systems. This general practice has serious shortcomings like design discontinuity, limited parallelisation, loss of information, and conversion errors. To overcome these shortcomings, macro-parametric approach (MPA), which is a history-based method of parametric CAD model exchange, has been proposed. The macro-parametric approach is a way to achieve compatible CAD model exchange amongst a variety of mutually incompatible CAD systems. CAD models can be exchanged in the form of a macro file that comprises a sequence of modeling commands. A standard macro file that contains a set of event-driven commands can transfer the designer intent such as parameters, features and constraints. Currently, STEP (STandard for the Exchange of Product model data) as an international standard (ISO-10303, Industrial automation systems and integration - Product data representation and exchange) for the computer-interpretable representation and the exchange of product model data is widely used. STEP is becoming the 'lingua franca' in the area of modelling and exchanging product data. One remaining problem of the using STEP as a neutral format is that it does not retain parametric information such as the designer intent but only the pure boundary representation (B-rep) of the CAD model. The B-rep model without parametric information presents difficulties for engineering changes and it may also lead to an unexpected distortion of shape. This research aims to investigate an exchange method that uses STEP/XML (extensible mark-up) technology to express a set of standard modeling commands extracted from CAD models created by Autodesk InventorTM, to enable the same CAD models are readable and shareable with other CAD application systems.

شناخت آسیب پذیری جمعیت و گروه های انسانی به عنوان اقدامی ابزاری در راستای پیشگیری از زایش فاجعه مبتنی بر زیستن در نواحی پر خطر مطرح است. تحلیل آسیب پذیری کانون‌های جمعیتی واقع در عرصه های خطر اقدامی علمی برای فراهم سازی زیر ساخت اطلاعاتی مناسب از درجه و میزان خطرپذیری از رخداد مخاطره است. بر اساس چنین دیدگاهی مسئله تحلیل آسیب پذیری ناشی از مخاطرات ژئومورفولوژیک فرونشست در جنوب شهر تهران مورد توجه قرار گرفته است. بدین منظور در ابتدا با استفاده از تکنیک تداخل سنجی راداری نرخ و دامنه فرونشست در محدوده مورد مطالعه استخراج گردید. سپس برای تولید نقشه فضایی عرصه های پر مخاطره نرخ و دامنه فرونشست به عنوان فاکتور عامل در زایش مخاطره به تحلیل گر سیستم در محیط GIS وارد گردید. نقشه خروجی معرف سلول‌های واجد ارزش متفاوت از فاکتور زایش مخاطره است. استخراج عرصه متعلق پهنه در معرض مخاطره نشان داد که از مجموع مساحت محدوده 7/12 درصد در پهنه های بسیار پرخطر، 7/14 در عرصه پرخطر،5/15 در عرصه نسبتاً پرخطر بیش از نیمی از محدوده (57درصد) در عرصه نسبتاً کم خطر قرار گرفته‌اند. برای ارزیابی میزان خطرپذیری، الگوی توزیع فضایی تأسیسات و ساخت‌وساز های موجود با نقشه عرصه های در معرض خطر هم نهاد گردید. مبتنی بر این اطلاعات و با استفاده از پیمایش میدانی اقدام به بررسی آسیب پذیری جمعیت ،مساکن و تأسیسات موجود در محدوده مورد مطالعه صورت پذیرفت. یافته های تحقیق موید آسیب پذیر بودن اکثر سکونت گاه‌ها و جمعیت ساکن درآنهاو تأسیسات موجود در محدوده می‌باشد. همچنین بر اساس پایش های میدانی صورت گرفته مشخص گردید که اکثر ساخت و سازهای موجود در منطقه غیر اصولی بوده که این امر باعث فراهم آوری زیرساخت آسیب پذیری برای مستحدثات در شرایط خطرپذیر است.

The extension of radix-4 algorithm to radix-16 to achieve the high throughput of 2.59 giga- samples/s for WPAN's.We are also reformulating radix-16 algorithm to achieve low-complexity and low area cost and high performance. Radix -16 FFT is obtained by cascaded the radix -4 butterfly units. It facilitates low-complexity realization of radix-16 butterfly operation and high operation speed due to its optimized pipelined structure. Besides, a new three-stage multiplier for twiddle factor multiplication is also proposed, which has lower area and power consumption than conventional complex multipliers. Equipped with those new performance-boosting techniques, overall the proposed radix-16 FFT processor is area-efficient with high data processing rate and hardware utilization efficiency. The control circuit of the proposed simplified radix-24 FFT SDF architecture is simpler than that of the direct radix-16 FFT SDF structure. The multiplier cost of the proposed FFT architecture is less than that of the previous FFT structures in 256-point FFT applications. The throughput of the proposed FFT processor is one sample per clock. Although the radix-16 FFT algorithm has Less computational complexity, the control circuit of the direct radix-16 SDF architecture for implementing radix-16 FFT is very complex. Thus, the efficient simplified radix-24 SDF structure, which is described in the next section, will be applied to radix-16 FFT algorithm.

Bali as one of the target areas of urbanization and mobilization is inseparable to the issues of immigrants. Sanur area, particularly the one that is known as a tourist area, has been most the target of the visits of immigrants seeking to improve the economy. Sanur Desa Pakraman Intaran of Denpasar has undergone transformation from a fishing village into a village that relies on tourism sector. Ideally, the immigrants or called as tamiu are obliged to report themselves to the head of the neighborhood or local prajuru adat/banjar for the creation of an orderly administration. However, in practice there are immigrants who have not cared to work on the rules. To overcome the problem, it is necessary to the efforts in the form of structuring the immigrants. Structuring the immigrants necessarily requires synergy between the village of service with pakraman in order to create the same understanding, vision and mission in order to control the immigrants.

Recently, smart grid networks are researched and developed for the greening of the energy consumption. When introducing these into the university or the community, it is required not only the wide area cooperation and the high-speed monitoring & control, but also the construction of the heterogeneous infrastructure with the security and the flexibility. In this paper, recent research on the Radio on Fiber (RoF) technologies are described, and the technology application to the university and/or community smart grid is suggested. And also it is proposed the wide area remote connection of heterogeneous cognitive radio networks by RoF-MIMO (Multiple Input Multiple Output) technologies. Network throughput and the network outage rate using various types of RoF-MIMO systems are calculated and compared. And it is shown that the distributed parallel RoF-MIMO can improve the throughput and the outage performance simultaneously. Prototyping Experiment is also conducted in the faculty building and confirms that the network outage is improved by the distributed parallel RoF-MIMO.

Drivers of Departure and Prospecting in Dispersing Juvenile Red Kites (Milvus milvus)

The social contract has been about rights and responsibilities in human societies. Facebook and its role in manufacturing and sustaining a global social contract, a new “we” is clearly one of the research areas that needs more attention. A new “we” is coming of age in the new age of connectivity and communication with a new outlook toward responsibility and rights at individual and collective levels. Facebook purports to build a new world based on connection and communication which is based on progress and prosperity. However, a fundamental factor and feature of Facebook that needs attention and more research is that people and users are becoming increasingly lonely, separated and independent from each other in this process while connecting and communicating with one another. This new social contract and “we” thus have the new features of the relationship between the human agency and his/her social structures. Cyberspace is the product of human agency and clearly creates and sustains a specific social structure. This research seeks to study the relationship between human agency, changing technical tools of communication and connection and emerging and evolving social structures and social contracts. Bandura’s “social cognitive theory” (2006) rejects a conflict and dichotomy between agency and social structure. As agency helps to build new social structures after destroying the old ones these new structures create and sustain a new social contract and “we” with a new sense of responsibility, obligations, and rights.

BackgroundThe impact of a given presynaptic neuron on the firing probability of the postsynaptic neuron critically depends on the number of functional release sites that connect the two neurons. One way of determining the average functional synaptic connectivity onto a postsynaptic neuron is to compare the amplitudes of action potential dependent spontaneous synaptic currents with the amplitude of the synaptic currents that are independent of action potentials ("minis"). With this method it has been found that average synaptic connectivity between glutamatergic CA3 and CA1 pyramidal cells increases from single connections in the neonatal rat, to multiple connections in the young adult rat. On the other hand, γ-aminobutyric acid (GABA)ergic interneurons form multiple connections onto CA1 pyramidal cells already in the neonatal rat, and the degree of multiple GABAergic connectivity is preserved into adulthood. In the present study, we have examined the development of glutamate and GABA connectivity onto GABAergic CA1 stratum radiatum interneurons in the hippocampal slice, and compared this to the connectivity onto CA1 pyramidal neurons.ResultsIn GABAergic interneurons in the CA1 stratum radiatum, irrespective of developmental stage, we found that the average amplitude of action potential dependent spontaneous AMPA receptor-mediated synaptic currents were of the same magnitude as the mini AMPA receptor mediated synaptic currents. This finding indicates that these GABAergic interneurons, in contrast to the CA1 pyramidal neurons, preserve single glutamate connectivity throughout development. For GABA connectivity, on the other hand, we found multiple functional synaptic connections onto the interneurons, as onto the pyramidal cells.ConclusionsThe results presented here confirm that glutamate and GABA synaptic connectivity develop very differently in the hippocampal CA1 region. Thus, whereas average GABA connectivity is multiple throughout the development, glutamate connectivity is unitary early in development. Our results further suggest that the development of glutamate synaptic connectivity differs markedly between pyramidal cells and GABAergic interneurons in stratum radiatum, such that a given presynaptic glutamatergic cell appears not allowed to increase its connectivity onto the postsynaptic stratum radiatum interneuron, as it may do onto the postsynaptic CA1 pyramidal cell.

As favelas e os condomínios fechados expressam a dualidade das formas de morar de ricos e pobres na metrópole paulistana. As ocorrências desses assentamentos acontecem desde a primeira metade do século XX, no caso das favelas, e a partir dos anos 1970, no caso dos condomínios e loteamentos fechados. Este trabalho pretende analisar e identificar tanto os espaços das moradias em condição de extrema vulnerabilidade, particularmente as favelas e unidades habitacionais localizadas em assentamentos periféricos precários, bem como as formas de estruturação do espaço de morar dos ricos e da classe média, destacando, preferencialmente, os condomínios horizontais fechados, como formas de moradia que representam os dois extremos da desigualdade socioterritorial existente no contexto urbano e metropolitano de São Paulo. Trataremos também de refletir sobre as novas formas de apropriação do espaço de morar dos ricos e dos pobres, procurando compreender se existe realmente um novo padrão de ocupação do solo na Região Metropolitana de São Paulo.

Experimental and discrete element methods were used to investigate the effects of distance between two preexisting cracks, bridge area (The length of the bridge area) and its angularities on the shear behaviour of bridge area. A punchthrough shear test was used to model the gypsum (concrete like) cracks under shear loading. Gypsum samples (concrete like) with dimension of 120 mm × 120 mm × 50 mm were prepared in the laboratory. Within the specimen model and near its four corners, four vertical notches were provided. Three different configuration systems were prepared for notches; i.e., paralell and in plane, inside echelon and outside echelon configuration systems, respectively. In these configurations, the length of cracks were taken as 2 cm, 4 cm and 6 cm based on the cracks configuration systems. Then, 9 specimens with different lengths of the bridge area and bridge area angles were prepared. Assuming a plane strain condition, special rectangular models were prepared with dimensions of 100 mm × 100 mm. similar to those for cracks configuration systems in the experimental tests i.e., 9 models with different lengths of the bridge area and bridge area angularities were prepared. The axial load was applied to the punch through the central portion of the model. This testing showed that the failure process was mostly governed by the lengths of the bridge area and bridge area angularities. The shear strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. It was shown that the shear behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the lengths of the bridge area. The strength of samples decreases by increasing the crack length. Also, the outside echelon crack configuration system has the maximum value of strength while the inside echelon crack configuration system has the minimum value of specimen's tensile strength. The failure pattern and failure strength are similar in both methods i.e., the experimental testing and the numerical simulation methods.

Wireless Local Area Networks (WLAN)s are today common for access to Internet; well-known and used is IEEE 802.11 standardized technology. Some drawbacks of the standardized distributed medium access scheme, Distributed Coordination Function (DCF) has resulted in considerations made to extend the DCF from single-hop communications to multi-hop. Multihopping has the potential to reduce energy consumption and increase throughput and coverage. The drawback is lack of Quality-of-Service (QoS) support, which already with single-hop communication was bad, but extending a communication between two peers to multi-hop significantly reduces the possibility to offer reliable transmissions. The contention-based medium access performed at each hop with the DCF results in large uncertainties as to when a packet arrives to its end-destination. There are two general approaches for extending the DCF with QoS functionality: 1. Allocate resources for a flow and 2. Assign a flow higher priority than other flows. My hypothesis is that for strict QoS guarantees, a reservation-based approach is the better one. This has been my motivation to design a new medium access protocol; based on the DCF, periodic time slots for QoS-demanding real-time applications are reserved. The Distributed Allocation of time slots for Real-time traffic (DARE) is unique as it totally distributed sets up an end-to-end reservation before the transmission of data begins, repairs broken reservations, support many periods and time slot sizes and distribute piggy-backed information even to a two-hop radius from a receiver. This thesis describes the DARE protocol and also presents results from comparisons of DARE, DCF and the IEEE 802.11 E standardized priority-based QoS medium access protocol Enhanced Distributed Channel Access (EDCA). Using simulations, this thesis shows that DARE offers constant end-to-end packet delay for a flow, very low average packet delay in the whole system and constant throughput. EDCA and DCF depend strongly on the total network load; average packet delay for a real-time flow increases rapidly with the surrounding load. DARE outperforms both DCF and EDCA when many flows are present, even in networks with frequent topology changes where reservations must be repaired. Thus, the reservation-based DARE protocol is the most suitable approach for extending DCF with QoS.

Strolling through street markets in Monk Kok, bypassing the cacophony of EDM from Lan Kwai Fong’s nightclubs, slurping soup noodles in a Sai Ying Pun local restaurant or taking a breather in Sun Yat Sen Memorial Park; while recording Hong Kong city sounds with Soundman OKM II binaural microphones I asked myself many times what I actually was doing. In two fieldwork sessions, one in February 2017 and one in March 2018 I was collecting sound recordings from various places in Hong Kong with a focus on the quarters of Sai Ying Pun on Hong Kong Island and Mong Kok on the Kowloon peninsula. While most parts of Hong Kong are characterized by a high density of inhabitants, Mong Kok stands out with up to 130,000 inhabitants per square kilometer. On top of that it is perennially frequented by both tourists and locals for shopping, food and entertainment. Sai Ying Pun is a gentrified residential neighborhood that became increasingly popular with expats due to the newly built MTR connection to the city center. It is also densely populated (57,000 inhabitants per square kilometer) and characterized by pencil towers (cf. Christ and Gantenbein) that are located along the steep slopes of Victoria Peak and on reclaimed land along Victoria Harbour. Yet, its streets are less crowded than those in Mong Kok and especially up the hills it can be relatively quiet. Analyzing the sounds of these neighborhoods provides means for a time considering comparison of intensities of activity and usage of public space. The cases of Mong Kok and Sai Ying Pun are especially interesting, because while both are shaped by its vertical expansion, Mong Kok has a much higher amount of visitors moving in and out horizontally. Sai Ying Pun instead feels more like a community, where people walk from flat to shop and back to flat, but due to the high amount of flats, it still has a density of shops to be characterized as downtown. Roughly Sai Ying Pun could be categorized as a residential area with a lot of shops, Mong Kok as a shopping area with a lot of residents. The use of in-ear microphones allows to reproduce the heard sounds three-dimensionally when played with headphones. This facilitates the understanding the actual experience of listening in places, even though it cannot substitute it. Listening with or without the microphones are two different things, and as I tried to listen to the city as casually as possible, the microphones felt like something that would interfere with a day-to-day Hong Kong listening experience. It seems that sound recordings are useful for typical soundscape studies, in which different city sounds are located, contextualized and distinguished into keynote sounds, signals, and sound marks (cf. Schafer). The actual experience of listening in a city thus seems unreproducible. In this paper, I want to address different aspects of comparison that are crucial for an anthropology of sound. I want to show that listening always involves a form of comparison. I argue that the comparability of sound recordings was crucial for the development of what is now called ethnomusicology. I want to stress the difference between listening to sound recordings and listening in situ. I will try to illustrate my point with examples from my research considering the soundscape of density in Mong Kok and Sai Ying Pun.