35,717 research outputs found
Construction heuristics for two-dimensional irregular shape bin packing with guillotine constraints
No full textThe paper examines a new problem in the irregular packingliterature that has existed in industry for decades;two-dimensional irregular (convex) bin packing with guillotineconstraints. Due to the cutting process of certain materials, cutsare restricted to extend from one edge of the stock-sheet toanother, called guillotine cutting. This constraint is commonplace in glass cutting and is an important constraints intwo-dimensional cutting and packing problems. In the literature,various exact and approximate algorithms exist for finding the twodimensional cutting patterns that satisfy the guillotine cuttingconstraint. However, to the best of our knowledge, all of thealgorithms are designed for solving rectangular cutting where cutsare orthogonal with the edges of the stock-sheet. In order tosatisfy the guillotine cutting constraint using these approaches,when the pieces are non-rectangular, practitioners implement a twostage approach. First, pieces are enclosed within rectangle shapesand then the rectangles are packed. Clearly, imposing this condition is likely to lead to additional waste. Thispaper aims to generate guillotine-cutting layouts of irregularshapes using a number of strategies. The investigation comparestwo two-stage approaches; one approximates pieces by rectangles,the other approximates pairs of pieces by rectangles usingphi-functions for optimal clustering. Both these approaches usestate of the art rectangle bin packing with guillotineconstraints. Further, we design and implement a one-stage approachusing a self-adapted forest search algorithm. Experimental resultsshow the one-stage strategy to produce good solutions in less timeover the two-stage approach
Personal exposure to source-specific particulate polycyclic aromatic hydrocarbons (PAHs) and systemic inflammation: the results from a cross-sectional study among the urban elderly in China
No full textEnvironmental exposure to ambient polycyclic aromatic hydrocarbons (PAHs) can disturb the immune response. However, the evidence on adverse health effects caused by exposing to PAHs emitted from specific sources among different vulnerable subpopulation is limited. In this cross-sectional study, we aimed to evaluate whether exposure to source-specific PAHs could increase the level of systemic inflammation in older adults. The present study included community-dwelling older adults and collected filter samples personal exposure to PM2.5 during the winter of 2011. Blood samples were collected after the PM2.5 sample collection. We analyzed PM2.5 bound PAHs and serum inflammatory cytokines (interleukin (IL)1β, IL6, and tumor necrosis factor alpha levels. The Positive Matrix Factorization model was used to identity PAHs sources. We used a linear regression model to assess the relative effects of source-specific PM2.5 bound PAHs on the levels of measured inflammatory cytokines. After controlling for confounders, exposure to PAHs emitted from biomass burning or diesel vehicle emission was found to be associated with increased levels of serum inflammatory cytokines and systemic inflammation. In summary, exposure to PAHs from certain specific sources of PAHs may significantly enhance systemic inflammation in the elderly. These findings highlight the importance of considering exposure sources in epidemiological studies and that of controlling exposures to organic materials from specific sources
Data for "Characterizations and potential formation pathways of atmospheric inorganic ions at a national background site in the northeastern Qinghai-Tibet Plateau during autumn season"
No full textData for "Characterizations and potential formation pathways of atmospheric inorganic ions at a national background site in the northeastern Qinghai-Tibet Plateau during autumn season
A single chamber stackable microbial fuel cell with air cathode
No full textA single chamber stackable microbial fuel cell (SCS-MFC) comprising four MFC units was developed. When operated separately, each unit generated a volumetric power density (P(max,V)) of 26.2 W/m(3) at 5.8 mA or 475 mV. The total columbic efficiency was 40% for each unit. Parallel connection of four units produced the same level of power output (P(max,V) of 22.8 W/m(3) at 27 mA), which was approximately four times higher than a single unit alone. Series connection of four units, however, only generated a maximum power output of 14.7 W/m(3) at 730 mV, which was less than the expected value. This energy loss appeared to be caused by lateral current flow between two units, particularly in the middle of the system. The cathode was found to be the major limiting factor in our system. Compared to the stacked operation of multiple separate MFCs, our single chamber reactor does not require a delicate water distribution system and thus is more easily implemented in pre-existing wastewater treatment facilities with serpentine flow paths, such as fixed-bed reactors, with minimal infrastructure changes.
Online algorithms for 1-space bounded multi dimensional bin packing and hypercube packing
No full textIn this paper, we study 1-space bounded multi-dimensional bin packing and hypercube packing. A sequence of items arrive over time, each item is a d-dimensional hyperbox (in bin packing) or hypercube (in hypercube packing), and the length of each side is no more than 1. These items must be packed without overlapping into d-dimensional hypercubes with unit length on each side. In d-dimensional space, any two dimensions i and j define a space P ij. When an item arrives, we must pack it into an active bin immediately without any knowledge of the future items, and 90 {ring operator}-rotation on any plane P ij is allowed. The objective is to minimize the total number of bins used for packing all these items in the sequence. In the 1-space bounded variant, there is only one active bin for packing the current item. If the active bin does not have enough space to pack the item, it must be closed and a new active bin is opened. For d-dimensional bin packing, an online algorithm with competitive ratio 4 d is given. Moreover, we consider d-dimensional hypercube packing, and give a 2 d+1-competitive algorithm. These two results are the first study on 1-space bounded multi dimensional bin packing and hypercube packing. © 2012 The Author(s).published_or_final_versionSpringer Open Choice, 28 May 201
On The Non-linear Distortion Effects in an OFDM-RoF Link
No full textRadio over Fiber (RoF) system is a promising technique for microcell and picocell applications for deployment of future ubiquitous wireless data networks. However, the performance of RoF systems can be severely degraded due to non-linear effects in the channel. Also, Orthogonal Frequency Division Multiplexing (OFDM), as a standard for broadband wireless networks, is being proposed for deployment with RoF systems to facilitate the total performance of a system. In this research, at first, the performance of OFDM-based RoF link with Mach-Zehnder modulator distortion effects has been analyzed at 5.8 GHz. Evaluation of mean-squared error of the proposed OFDM-RoF system was carried out to compare with the conventional single carrier system based RoF link after the modulator distortion case and also for fixed Signal to Noise Ratio (SNR) of 20 dB using undistorted OFDM signal. Later, nominal and offset biasing pre-distortion techniques are applied in proposed system to linearize the OFDM-RoF link. Thus, finally a comparison between the aforementioned pre-distortion techniques applied showed important observation in terms of distortion-free dynamic range and SNR to choose offset pre-distortion technique for our proposed system
Universitätsbibliothek Marburg Ms. or. 41: [Mahmud Han bin Mustafa el-muzaffer dâimâ, Erlass]
No full textElektronische Reproduktion von: [Handschrift] Universitätsbibliothek Marburg Ms. or. 41: [Mahmud Han bin Mustafa el-muzaffer dâimâ, Erlass]. - Konstantinopel, 1143/1722. - 1 Blatt. -
Standort: Universität Marburg, Universitätsbibliothek. -
Signatur: Ms. or. 41. -
Bemerkungen: In arabischer Schrift, osmanisch. -
Digitalisiert 202
Tarih-i Sultan Mehmet Han (Bin) İbrahim Han
No full textTez konusu olarak seçtiğimiz "Tarih-i Sultan Mehmed Han (Bin) İbrahim Han" adındaki eser Topkapı Sarayı Müzesi Kütüphanesinde "Tarih-i Yang adı" ile kayıtlı olup 17. yy Osmanlı Tarihi kaynaklarından biridir. Katib Mehmed Necati tarafından 1665 tarihinde kaleme alınmıştır. Eserde Töprülü Fâzıl Ahmed Paşa komutasındaki Osmanlı Ordusunun 19 Mart 1663 tarihinde İstanbul'dan hareket ederek Uyvar Kale'sinin fethi ve Osmanlılar için elverişli şartlar taşıyan 1664 Vasvar anlaşmasının imzalanmasından sonra ordunun Temmuz 1665'te Edirne'ye dönüşüyle sonuçlanan Avusturya Seferim anlatmaktadır. Ayrıca eserin başında İstanbul-Budin arasındaki menziller (durak, mola yerleri) nin listesi verilmiştir. Çalışmamızın I. bölümünde konunun daha iyi anlaşılabilmesi için 1663 e kadar olan Osmanlı- Avusturya münasebetleri ve 1663 Avusturya Seferi hakkında eldeki kaynaklara dayanarak kısa bilgiler verdik. Ayrıca seferin baş kahramanı olan Fâzıl Ahmed Paşa'nın hayatı hakkında da bilgiler verdik. E. Bölüm de ise el yazması bir eser olan kitabın şekil ve içerik olarak tanıtımını yaptıktan sonra metni yeni harflerle aktardık. Çalışmamızın sonuna ise metnin fotokopisi, Vasvar Anlaşması metni ve Yol güzergâhım gösteren bir haritayı eklemeyi uygun gördük. Çalışmamızda 17. yy Osmanlı Tarihine ait bir kaynağı yeni harflere çevirip tatıtımını yaparak gün ışığına çıkarılmasını amaçladık. Araştırıcı ve ilgililere yararlı olması temennimizdir.The work of literature called as "Tarih-i Sultan Mehmed Han (Bin) tbrahim Han", which we have chosen as our thesis subject, was registered as "Tarih-i Yang" in Topkapi Palace Museum Library and it was one of the Ottoman History sources. It was written by Katib Mehmed Necati in 1665. This book was explaining the conquest of Uyvar Castle by the move of the Ottoman Army, which was in the command of Köprülü Fâzıl Ahmed Pasha, from Istanbul in 19 March 1663 and the return of the army from Edirne in July 1665 which was resulted in Austria War after the sign of 1664 Vasvar Agreement which had converient conditions for the Ottoman Empire. In addition to these, in the beginning of this book the range (stopping-place, rest places (lists) between Istanbul&Budin was presented. In the first part of our work to make the subject more clear, we gave some information about the relation between the Ottoman& Austria up to 1663 and 1663 Austria war by depending on existing sources. In addition, we gave some information about Fâzıl Ahmed Pasha who was the leader hero of this war. In the second part, after we introduced illustration&content of this handwritten book, we translated it to new letters. And we found acceptable to put text's photocopy, text of Vasvar agreement and the map that shows the road way at the end of our work. We aimed to make this book, that belongs to 17th century Ottoman History, come to light by translating it to new letters and by introducing it. We wish mat, it will be useful for researchers&for those concerned
Static and Dynamic Properties and Temperature Sensitivity of Emulsified Asphalt Concrete
No full textAsphalt concrete is a typical rheological material, which is hard brittle at low temperature and reflects soft plastic facture at high temperature; the temperature has a great influence on the mechanical properties of asphalt concrete. In order to eliminate the environmental pollution caused by hot asphalt construction, cationic emulsified asphalt can be used. This paper transforms the temperature control system for static and dynamic triaxial test equipment, which has achieved static and dynamic properties of emulsified asphalt concrete under different temperatures, and researched the temperature sensitivity of emulsified asphalt concrete materials including static stress-strain relationship, static strength, dynamic modulus of elasticity, damping ratio, and so on. The results suggest that (1) temperature has a great influence on the triaxial stress-strain relationship curve of the asphalt concrete. The lower the temperature, the greater the initial tangent modulus of asphalt concrete and the higher the intensity; the more obvious the softening trend, the smaller the failure strain of the specimen and the more obvious the extent of shear dilatancy. When the temperature is below 15.4°C, the temperature sensitivity of the modulus and strength is stronger significantly. (2) With the temperature rising, the asphalt concrete gradually shifts from an elastic state to a viscoelastic state, the dynamic modulus gradually reduces, and the damping ratio increases. When the temperature is above 15.4°C, the temperature sensitivity is obviously stronger for the dynamic elastic modulus and damping ratio. (3) The static and dynamic properties of asphalt concrete are very sensitive to the temperature. The test temperature should be made clear for the static and dynamic tests of asphalt concrete. The specimen temperature and the test ambient temperature must be strictly controlled
Strip Packing vs. Bin Packing
No full textIn this paper we establish a general algorithmic framework between bin packing and strip packing, with which we achieve the same asymptotic bounds by applying bin packing algorithms to strip packing. More precisely we obtain the following results: (1) Any offline bin packing algorithm can be applied to strip packing maintaining the same asymptotic worst-case ratio. Thus using FFD (MFFD) as a subroutine, we get a practical (simple and fast) algorithm for strip packing with an upper bound 11/9 (71/60). A simple AFPTAS for strip packing immediately follows. (2) A class of Harmonic-based algorithms for bin packing can be applied to online strip packing maintaining the same asymptotic competitive ratio. It implies online strip packing admits an upper bound of 1.58889 on the asymptotic competitive ratio, which is very close to the lower bound 1.5401 and significantly improves the previously best bound of 1.6910 and affirmatively answers an open question posed [5]
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