1,913,093 research outputs found
A multi-exit recirculating optical packet buffer
No full textWe propose a new type of recirculating buffer, the multiexit buffer (MEB), for use in asynchronous optical packet switches with statistical multiplexing, operating at speeds of 40-100 Gb/s. We demonstrate that the use of this type of buffer dramatically reduces the packet loss for a given buffer depth, thus reducing the buffer depth requirements and the overall cost of the optical packet switching. Physical layer simulation results show that it is possible to build this type of buffer with currently available active components. A hybrid optoelectronic control system is proposed, which allows control of the MEB with a minimum number of active components
Buffer overflow támadások bemutatása, sérülékeny rendszerek készítése
No full textAz informatikai rendszerek megbízható és megfelelő működéséhez elengedhetetlen azok biztonsága. Azonban sajnos számtalan olyan szoftver kerül piacra, amely rendelkezik valamilyen sérülékenységgel, amit a támadók kiaknázhatnak. A szakdolgozatom egy viszonylag kevéssé ismert, de annál nagyobb horderejű, és aránylag gyakran előforduló kibertámadási módszert, a buffer overflow támadásokat mutatja be. Az elején bevezetem a témát, és ismertetem annak relevanciáját, alapötletét. Ezt követően bemutatásra kerülnek a buffer overflow támadások alapelvei, valamint a módszer teljes megértéséhez szükséges egyéb szakmai ismereteket is részletesen tárgyalom. Ezután a stack alapú buffer overflow támadásokat ismertetem, és áttekintem a rosszindulatú személyek által használható főbb technikákat, majd áttérek az ellenük használható védekezési módszerek alapos bemutatására. Mivel egy védekezési technika sem tökéletes, ezért fontosnak tartottam pár ezeket kijátszó stratégia leírását is. Az elmélet taglalása után virtuális gépek segítségével, gyakorlati példákon keresztül demonstrálom a stack alapú buffer overflow támadásokat, és azok kivitelezését.BSc/BAProgramtervező informatikus BScN.I
The Central European buffer zone
No full textThis paper considers the creation of a new region in Europe since the opening of the borders following the so-called "revolutions" in East-Central Europe. The "buffer zone" consists of a privileged group of post-Communist countries sandwiched between some of the most affluent countries of the European Union on the one side and countries with collapsing, unreformed or backward economies on the other. This paper considers the countries: Poland, Czech Republic, Hungary and Slovakia in terms of the circulation of GOODS, CAPITAL and PEOPLE around the region. The Central European buffer zone countries represent the most successful group of countries in terms of economic and political reform and social stability. This is both a cause and consequence of their attracting investment, tourism and other forms of economic and cultural communication from their neighbours to the west -. Especially Germany and Austria. For the countries to the East and South of the buffer zone, their prosperity and the possibility of crossing into the buffer zone but not further, creates an attraction for visitors from the East who arrive for settlement for work, for shopping, for trading or for establishing businesses. The establishment of cross-border communications depends to a large extent on reviving family, ethnic and cultural ties which were for many years severed by Communism.
A Buffer Stocks Model for Stabilizing Price in Duopoly-Like Market
No full textThis paper presents the staple-food distribution problem in agro-industry. There is a great difference
of staple-food supplies in the harvest-season and in the planting-season meanwhile the demand is relatively
constant. This situation will trigger price-volatility and shortage of staple-food, and it causes opportunity-losses for the stakeholders (producer, consumer, wholesaler/trader, and the government). For stabilizing the
price, the government has several stabilization policies; one of them is market-intervention policy by using
buffer-stocks schemes. The market-intervention policy should be utilized for improving producer’s profit, for
cutting consumer’s expenditure, and for sustaining wholesaler’s margin-profit by implementing price-support
and price-stabilization. In duopoly-like market, we assume that there are only two market-players in the
distribution system. The objective of this research is to determine the instruments for operating Market-Intervention Program which consist of the quantity, time, and price of the buffer-stocks schemes. The problem
was solved using 3 approaches. First, a comparative cost/benefit analysis between free-market and
intervention-market can be used to formulate the objective function of each stakeholders. Second, the
integration of optimization model and econometrics model were use to develop the decision-variables subject
to the expectation of stakeholders, the buffer-stocks requirement, and the dynamics price equilibrium
properties. Third, model market with Inventory was applied for solving the market-price equilibrium. The
result could be used to analyze such the staple-food distribution system, incorporating the configuration of
duo-producers, duo market-buyers, and duo-consumers.
Keywords: buffer-stocks, duopoly-like market, market-intervention program, model market with inventory,
and staple-food distribution system
Optimal buffer size definition of automatic production lines using simulation
No full textopenOttimizzazione delle dimensioni di un buffer industriale grazie all'utilizzo di un software di simulazione che lavora con i dati acquisitiOptimization of the size of an industrial buffer thanks to a simulation software that works with our acquired data
A Buffer Stocks Model for Stabilizing Price of Commodity under Limited Time of Supply and Continuous Consumption
No full textStaple foods, in developing countries especially in Indonesia, have extremely volatile among harvest
and planting season caused by inelastic of supply-demand and price disparity. When a staple food is shortage
in market, it will trigger crisis of economics, political and social because it concerns with food security. This
paper develops a buffer stock model for stabilizing price of commodity under limited time of supply and
continuous consumption. The performance criterion of model will consider financial loss of producer, consumer
and government side when market is interfered by price-stabilization program and price-support program
simultaneously. The price fluctuation will be stabilized by market operation where buffer stocks are bought
from domestic and import supply point. This paper provides a price band policy that attempts to bound
domestic price variation between a set of upper and lower bounds on the level of domestic prices. We consider
three sets of problems reflecting different three prices elasticity from 4 period of supply and demand.
Numerical examples are found to be consistent with empirical estimates regarding the relationship price
elasticity with price band and with government budget for the agenda of assisting household to assure
availability a staple food with enough amounts at rational prices.
Keywords: buffer stocks, price band, stabilization, limited time of supply, staple foods
A Buffer Stock Model to Ensure Price Stabilization and Availability of Seasonal Staple Food under Free Trade Considerations
No full textThe price volatility and scarcity have been became a great problem in
the distribution system of seasonal staple food produced by agro industry. It has
salient supply disparity during the harvest and planting season. This condition
could cause disadvantages to the stakeholders such as producer, wholesaler,
consumer, and government. This paper proposes a buffer stock model under free
trade considerations to substitute quantitative restrictions and tariffs by indirect
market intervention instrument. The instrument was developed through buffer
stock scheme in accordance with warehouse receipt system (WRS) and collateral
management system. The public service institution for staple food buffer stock
(BLUPP) is proposed as wholesaler’s competitor with main responsibility to
ensure price stabilization and availability of staple food. Multi criteria decision
making is formulated as single objective a mixed integer non linear
programming (MINLP). The result shows that the proposed model can be
applied to solve the distribution problem and can give more promising outcome
than its counterpart, the direct market intervention instrument.
Keywords: BLUPP; buffer stocks; indirect market intervention; MINLP; price
stabilization; staple food availability; warehouse receipt system
Buffer Block Planning for Interconnect-Driven Floorplanning
No full textThis paper studies buffer block planning for interconnect-driven floorplanning in deep submicron designs. We first introduce the concept of feasible region (FR) for buffer insertion, and derive closed-form formula for FR. We observe that the FR for a buffer is quite large in general even under fairly tight delay constraint. Therefore, FR gives us a lot of flexibility to plan for buffer locations. We then develop an effective buffer block planning (BBP) algorithm to perform buffer clustering such that the overall chip area and the buffer block number can be minimized. To the best of our knowledge, this is the first in-depth study on buffer planning for interconnect-driven floorplanning with both area and delay consideration
BUFFER STOCK MODEL FOR STABILIZING PRICE WITH CONSIDERING THE EXPECTATION STAKEHOLDERS IN THE STAPLE-FOOD DISTRIBUTION SYSTEM
No full textThe extremely different supplies between the harvest season and the planting season are one
of serious problem in the staple-food distribution system. In free-market mechanism, this
extreme difference will trigger price-volatility and shortage of staple-food. This situation
causes opportunity-losses for the stakeholders (producer, consumer, agent and government) in
the staple-food distribution system. The government has got incurred losses because the
government cannot achieve food-security for the households. The government has several
price stabilization policies; one of them is market intervention policy by using buffer stock
schemes to stabilize price and to reduce losses for the stakeholders. The objective of this
research is to determine the buffer stock schemes required for market-intervention program.
In the previous researches, the buffer stock models have been developed separately based on
optimization and econometrics methods. Optimizations methods have been used to determine
the level of availability with schemes consist of time and quantity of buffer stock.
Econometrics methods have been used to determine the equilibrium price by using the
selling-price and the amount of buffer stock. In this research, the integration of optimization
model (multi-objectives programming) and econometrics model are used to develop a buffer
stock model with the decision variables that consist of quantity, time, and price.
Key Words: Buffer Stock Model, Market-Intervention, Price-Stabilizatio
Buffer-aided cooperative networks
No full textIn this thesis new methods are presented to achieve performance enhancement in wireless cooperative networks. In particular, techniques to improve diversity gain, throughput and minimise the transmission delay are described.
A buffer-aided amplify-and-forward max-link relay selection scheme for both symmetric and asymmetric channels is introduced. This approach shows that the max-link scheme is most effective over the traditional max-SNR scheme when the source-to-relay and relay-to-destination links are symmetric. The closed form expressions for the outage probability and average packet delay of the proposed scheme under both symmetric and asymmetric channel configurations is derived. The diversity order and the coding gain of the AF max-link scheme is analytically provided. Then a novel relay selection scheme with significantly reduced packet delay is proposed. Both the outage performance and average packet delay of the proposed scheme are analysed. The analysis shows that, besides the diversity and coding gains, the proposed scheme has average packet delay similar to that of a non buffer-aided relay system when the channel SNR is sufficiently high thereby.
A novel buffer-aided link selection scheme based on network-coding in a multiple hop relay network is proposed. Compared with existing approaches, the proposed scheme significantly increases the system throughput. This is achieved by applying data buffers at the relays to decrease the outage probability and using network-coding to increase the data rate. The closed-form expressions of both the average throughput and packet delay are derived. The proposed scheme has not only significantly higher throughput than both the traditional and existing buffer-aided max-link scheme, but also smaller average packet delay than the max-link scheme.
A decode-and-forward buffer-aided relay selection for the underlay cognitive relay networks in the presence of both primary transmitter and receiver is presented. A novel buffer aided relay selection scheme for the cognitive relay network is proposed, where the best relay is selected with the highest signal-to-interference-ratio among all available source-to-relay and relay-to-destination links while keeping the interference to the primary destination within a certain level. A closed-form expression for the outage probability of the proposed relay selection scheme is obtained.
Finally, A novel security buffer-aided decode-and-forward cooperative wireless networks is considered. An eavesdropper which can intercept the data transmission from both the source and relay nodes is considered to threaten the security of transmission. Finite size data buffers are assumed to be available at every relay in order to avoid having to select concurrently the best source-to-relay and relay-to-destination links. A new max-ratio relay selection policy is proposed to optimise the secrecy transmission by considering all the possible source-to-relay and relay-to-destination links and selecting the relay having the link which maximises the signal to eavesdropper channel gain ratio. Two cases are considered in terms of knowledge of the eavesdropper channel strengths: exact and average gains, respectively. Closed-form expressions for the secrecy outage probability for both cases are obtained. The proposed max-ratio relay selection scheme is shown to outperform one based on max-min-ratio relay scheme
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