Generalized relaxed elastic line on an oriented surface

We study a relaxed elastic line in the general case on an oriented surface. In particular, we obtain a differential equation with three boundary conditions for a generalized relaxed elastic line. Then we analyze the results in a plane, on a sphere, on a cylinder, and on the geodesics of these surfaces.Вивчається релаксована пружна лiнiя у бiльш загальному випадку на орiєнтованiй поверхнi. Зокрема, отримано диференцiальне рiвняння з трьома граничними умовами для узагальненої релаксованої пружної лiнiї. Отриманi результати проаналiзовано на площинi, сферi, цилiндрi та на геодезичних цих поверхонь

\u27Utjecaj predsjetvene pripreme, vremena sjetve, zaštićenog prostora i klimatskih čimbenika na klijavost sjemena vrste Acer pseudoplatanus L.

In this study, the effects of different sowing environment (greenhouse and nursery), pretreatment (cold moist stratification), different sowing time (autumn, spring and summer) and some climate factors (air temperature, relative air humidity, soil temperature and soil moisture) on the germination of Acer pseudoplatanus L. seeds were studied. Seeds were harvested from the tree located in the Karadeniz Technical University campus. Three different germination trials were carried out; (1) direct sowing in autumn after seed collection (Control), (2) sowing stratified seeds in spring (Stratification-1) and (3) sowing stratified seeds in summer (Stratification-2). During the germination trial processes, air temperature, relative air humidity, soil temperature and soil moisture were measured periodicaly. Thus, the germination percentage changes in different sowing environments have been established on the basis of some climate factors. Higher germination percentages were obtained in the autumn (Control) compared to the spring (Stratification-1) and summer (Stratification-2) sowings. The highest percentages of germination were ­determined in the control trials (70% in greenhouse and 58% in nursery). Obtained germination results based on different sowing times revealed secondary dormancy in Acer pseudoplatanus L. seeds. It has been determined that the mean germination time in the greenhouse (12 days) was shorter than the mean germination time in the nursery (18 days). In addition, the obtained results showed that stratification and sowing time have a positive effect on the mean germination time in the greenhouse. Because of getting the best germination rates, keeping some climate ­factors constant (21.0-24.9 °C air temperature; 17.0-19.9 °C soil temperature; 63.0-68.9% relative air humidity; 60.0-67.9% soil moisture) during the vegetative propagation practices in the greenhouse, should affect mass ­seedling production in Acer pseudoplatanus L.Istraživan je utjecaj zaštićenog prostora (staklenik) i rasadnik, predsjetvene pripreme sjemena (hladno-vlažna stratifikacija), različitog godišnjeg doba sjetve (jesen, proljeće i ljeto) i nekih klimatskih čimbenika (temperatura zraka, relativna vlažnost zraka, temperatura tla i vlaga tla) na klijavost sjemena Acer pseudoplatanus L. Sjeme je sakupljeno sa stabala u kampusu Tehničkog sveučilišta Karadeniz. Provedena su tri različita ispitivanja klijanja; (1) izravna sjetva u jesen nakon sakupljanja sjemena (Kontrola), (2) sjetva stratificiranog sjemena u proljeće (Stratifikacija-1) i (3) sjetva stratificiranog sjemena ljeti (Stratifikacija-2). Tijekom procesa klijanja povremeno su mjerene temperatura zraka, relativna vlažnost zraka, temperatura tla i vlaga tla. Na taj način su utvrđene promjene u postotku klijavosti u različitim sjetvenim okruženjima pod utjecajem određenih klimatskih čimbenika. Viši postotci klijavosti zabilježeni su u slučaju jesenske sjetve (Kontrola) u usporedbi s proljetnom (Stratifikacija-1) i ljetnom sjetvom (Stratifikacija-2). Najveći postotak klijavosti utvrđen je u kontrolnim ispitivanjima (70% u stakleniku i 58% u rasadniku). Prikupljeni rezultati klijavosti tijekom različitog perioda sjetve otkrili su sekundarno mirovanje kod sjemena Acer pseudoplatanus L. Utvrđeno je da je srednje vrijeme klijanja u stakleniku (12 dana) bilo kraće od prosječnog vremena klijanja u rasadniku (18 dana). Osim toga, dobiveni rezultati pokazali su da stratifikacija i vrijeme sjetve pozitivno utječu na srednje vrijeme klijanja u stakleniku. Održavanje nekih klimatskih čimbenika konstantnima (temperatura zraka 21.0-24.9 °C; temperatura tla 19.0-19.9 °C; relativna vlažnost zraka 63.0-68.9%; vlažnost tla 60.0-67.9%) tijekom vegetativnog razmnožavanja u stakleniku bi trebalo utjecati na masovnu proizvodnju sadnica u Acer pseudoplatanus L., a u svrhu postizanja najboljih rezultata klijavosti

On Rectifying Dual Space Curves

We give some characterizations of the rectifying curves in the dual space and show that rectifying dual space curves can be stated with the aid of dual unit spherical curves. Thus, we have a link between rectifying dual space curves and classical surfaces in the Euclidean three-space

Mekansal ve kentsel bağlamda ‘ortak çalışma mekanı’ kavramı: Kolektif House üzerinden bir inceleme

The concept of ‘Work’ and ‘Workplace’ started to change in recent decades in parallel with developments in information and communication Technologies. New ways of working have been defined as flexible, mobile and multi-locational. Co-working spaces have emerged worldwide as a new type of workspace concept. These places offer a flexible and appropriate work environment with various usage options. The aim of the study is to define the characteristics and development of the co-working space concept and analyzing the urban and spatial context as well as design criteria, the spatial solution, material and furniture selection of the selected case. In this study the case of ‘Kolektif House’ a co-working space, in Levent district in İstanbul has been selected, as the location can be defined as the central commercial district of the city. The space is created by refunctioning a part of an old factory-building which is evaluated as a sustainable devolepment project. The data used in this study is based on architectural drawings, visual materials, interviews, observations, as well as a literature review. The study demonstrates that changing work habits and user needs created new types of working place and in the selected case the created value in urban and spatial context by re-functioning an existed building was found to be positive.“İş” ve “İş yeri” kavramı son yıllarda bilgi ve iletişim teknolojilerindeki gelişmelere paralel olarak değişmektedir. Yeni çalışma yöntemleri; esnek, mobil ve çok konumlu olarak tanımlanmıştır. Ortak çalışma alanları (Co-working space), dünya çapında yeni bir çalışma alanı konsepti olarak ortaya çıkmıştır. Farklı kullanım biçimlerine sahip bu alanlar esnek ve uygun bir çalışma ortamı vaad etmektedir. Bu çalışmada; Ortak Çalışma Alanı kavramı tanımlanarak özellikleri ve gelişimi incelenmiş, seçilen örnek üzerinden kentsel ve mekansal bağlamda analiz edilerek, tasarım kriterleri, mekansal çözüm ve donatıları incelenmiştir. Çalışma kapsamında İstanbul’un merkezi ticaret bölgesi olarak tanımlanabilecek Levent ilçesinde yer alan “Kolektif House” mekanı incelenmiştir. Alan, orjinal işlevini yitirmiş eski bir fabrika binasının sürdürülebilir bir gelişme projesi olarak değerlendirilmesiyle dönüştürülmüştür. Çalışmada kullanılan veriler; literatür araştırması, çizimler ve görsel materyaller, görüşmeler ve gözlemlere dayanmaktadır. Değişen çalışma alışkanlıklarının ve kullanıcı ihtiyaçlarının yeni çalışma mekanları yarattığı ve seçilen örnekte yeniden işlevlendirme sonucu üretilen mekan ile kentsel ve mekansal bağlamda yaratılan değerin pozitif olduğu düşünülmektedir.Publisher's Versio

Combined use of congestion control and frame discarding for Internet video streaming

Cataloged from PDF version of article.Increasing demand for video applications over the Internet and the inherent uncooperative behavior of the User Datagram Protocol (UDP) used currently as the transport protocol of choice for video networking applications, is known to be leading to congestion collapse of the Internet. The congestion collapse can be prevented by using mechanisms in networks that penalize uncooperative flows like UDP or employing end-to-end congestion control. Since today’s vision for the Internet architecture is based on moving the complexity towards the edges of the networks, employing end-to-end congestion control for video applications has recently been a hot area of research. One alternative is to use a Transmission Control Protocol (TCP)-friendly end-to-end congestion control scheme. Such schemes, similar to TCP, probe the network for estimating the bandwidth available to the session they belong to. The average bandwidth available to a session using a TCP-friendly congestion control scheme has to be the same as that of a session using TCP. Some TCP-friendly congestion control schemes are highly responsive as TCP itself leading to undesired oscillations in the estimated bandwidth and thus fluctuating quality. Slowly responsive TCP-friendly congestion control schemes to prevent this type of behavior have recently been proposed in the literature. The main goal of this thesis is to develop an architecture for video streaming in IP networks using slowly responding TCP-friendly end-to-end congestion control. In particular, we use Binomial Congestion Control (BCC). In this architecture, the video streaming device intelligently discards some of the video packets of lesser priority before injecting them in the network in order to match the incoming video rate to the estimated bandwidth using BCC and to ensure a high throughput for those video packets with higher priority. We iiidemonstrate the efficacy of this architecture using simulations in a variety of scenarios.Yücesan, OngunM.S

Functionalization of Metal-Organic Framework Nanochannels for Water Transport and Purification

Artificial water nanochannels (AWCs) have drawn great attention due to their potential use in water purification. Herein, we propose an AWC design, which is based on coordinatively functionalizing unsaturated metal sites found in metal-organic frameworks (MOFs) with one-dimensional nanochannels. As a computational demonstration, we consider two MOFs, namely, Ni-CPO-27 and Ni-CPO-54, and graft proline, imidazolecarboxylic acid, imidazolecarboxaldehyde, pyrazolecarboxylic acid, and pyrazole carbaldehyde molecules into the MOF nanochannels. To assess the strength of the molecule-metal binding, binding energies were calculated using density functional theory. The results indicate that the MOFs containing either proline or 2-imidazolecarboxylic acid form water-stable AWCs with binding energies twice that of the binding energy of water. To shed light on the water diffusion mechanism in the proline-Ni-CPO-27/54 and 2-imidazolecarboxylic-Ni-CPO-27/54 AWCs, molecular dynamics simulations were performed to calculate the mean-squared displacement of water molecules and nonbonded interaction energies between select pairs of atoms in water and coordinated molecules were analyzed. It was found that the fastest water diffusion occurs in proline-Ni-CPO-54 with a self-diffusion coefficient of 7.2 ± 0.5 × 10-8 cm2/s. In comparison, the fastest water self-diffusion coefficient reported in a carbon nanotube-based AWC is 9 × 10-6 cm2/s. Nonbonded interactions between specific atom pairs regulate water diffusion in the functionalized MOF nanochannels. In particular, the change in water mean-squared displacement with changing water loading correlates well with the nonbonded energies between the partially positively charged hydrogen atoms in water and the partially negatively charged oxygen and nitrogen atoms in the proline and 2-imidazolecarboxylic acid molecules. The results presented herein indicate that water-stable MOFs could perform well as AWCs, thereby lending support to the further design and synthesis of MOF-based AWCs for water purification

Çekyat Üretiminde Öncelikli Hedef Programlama İle Bütünleşik Üretim Planlaması Aggregated Production Planning in Sofa Production By Preemptive Goal Programming Approach

Bu çalışmanın amacı, mobilya endüstrisinde çekyat üretimi yapan bir işletmenin bütünleşik üretim planlama faaliyetleri için öncelikli hedef programlama yaklaşımının kullanılabilirliğini göstermektir. Karar verici için iki farklı bütünleşik üretim planı önerisi yapılmıştır. Planlardan biri iki öncelikli hedef programlama modeli kullanılarak yapılan bütünleşik üretim planıdır. Birinci öncelik hedeflenen kar miktarıdır, ikinci öncelik ise hedeflenen üretim miktarı ve hat düzgünleştirmedir. Birinci ve ikinci planda aynı kar miktarı hedeflenmesine rağmen, ikinci planda iş istasyonlarının çalışma süreleri mümkün olduğunca yakın olması istenmiştir. Böylece iş istasyonlarının boşta bekleme süreleri azalacaktır. Yapılan bu çalışma sonucunda üretim planlama ve kontrol faaliyetlerinin işletme verimliliği üzerindeki önemi ortaya koyulmuştur. Önerilen üretim planı modeli esas alınarak gelecek dönemlerde, model üzerinde ürün sayısı, çeşidi ve planlama dönemi sayısı değiştirilerek farklı amaçlar doğrultusunda farklı sonuçlar elde edilebileceği önerilmektedir. In this study, it is aimed to apply aggregate production planning in a furniture company which produces sofa. Preemptive goal programming has been used which is an effective method in aggregate production planning solution. Two different aggregate production plans have been suggested. One of the plans is two priority goal programming. First priority is targeted profit, second is both production size and line smoothing. Although first and second plans aims same profit level, in the second plan working time of work stations wanted to as near as possible. By this way work station’s spare times will be reduced. As a result of this study, the importance of production planning and control activities on the corporate profitability has been showned and it is concluded that scientific methods should be used. Based on the suggested production plan, it is possible to get new results by changing product numbers, types and number of planning periods

YSA, ARIMA ve ARIMAX Yöntemleriyle Satış Tahmini: Beyaz Eşya Sektöründe bir Uygulama Sales Forecast with YSA, ARIMA and ARIMAX Methods: An Application in the White Goods Sector

Beyaz eşya sektörü Türkiye’nin istihdama ve ihracata verdiği katkılardan dolayı lokomotif sektörlerinden biridir. Son yıllarda yaşanan teknolojik gelişmeler ve küreselleşme ile birlikte yaşanan zorlu rekabet koşullarından etkilenen sektörler içerisinde yer almaktadır. Etkili bir üretim planlaması; mevcut talebi zamanında ve minimum maliyetle karşılayabilmelidir. Mevcut talebi tespit edebilmek ise iyi bir satış tahmini ile mümkün olmaktadır. Bu yönüyle satış tahmini, karar vericilerin başarılı olmalarında önemli bir rol oynamaktadır. Bu çalışmada, beyaz eşya sektörü için bir satış tahmini modeli önerilmiştir. Bulaşık makinesi, çamaşır makinesi, buzdolabı, küçük ev aletleri ve televizyon ürünleri için 46 aylık satış verileri kullanılmıştır. Satışları etkileyen faktörler olan döviz kuru, tatil günleri, tüketici güven endeksi (TGE), üretici fiyat endeksi (ÜFE) ve bölgedeki konut satışları, açıklayıcı değişken olarak kullanılmıştır. Yapay sinir ağları (YSA), ARIMA ve ARIMAX yöntemleri ile elde edilen sonuçlar, ortalama kareli hata (OKH) performans kriterine göre kıyaslandığında en isabetli tahminlerin YSA yöntemi kullanılarak elde edildiği söylenebilir. The white goods sector is one of the locomotive sectors of the country due to the contributions of employment and exports. The technological developments and globalization experienced in recent years are among the sectors that are affected by the changing and competitive conditions. Efficient production planning; must meet the current demand in time and with minimal cost. Determining the current demand is possible with a good sales forecast. In this sense, sales forecasting plays an important role in the success of decision makers. In this study, the sales forecast model for the white goods sector was proposed. The 46 months’ sales data have been used for dishwashers, refrigerators, small house appliances and televisions. The exchange rate, holiday days, consumer confidence index, producer price index, housing sales in the region are used as explanatory variable. It can be said that the most accurate estimates are obtained by using the ANN method when mean squared error (MSE) compared which is the performance criterion

Social and Moral Elements in the Poem “Il Giorno” by Giuseppe Parini

Giuseppe Parini is considered one of the pioneers of the 18th century Italian Enlightenment period. Among many of his works which he wrote during his entire life, the most known is his work entitled Il Giorno which is composed of four main parts where different periods of a young aristocrat’s daily life flow are described. This work is also a kind of ironic poem where the mastership of the poet can be seen. With the effects of the Enligtenment period in which he lived, Parini defends the values of equality by providing examples. He criticizes the way of thinking and living of the aristocratic society of the period. According to him, the problems of inequality in society can be resolved only by way of education. The reflections of his life experiences, such as teaching, being a clergyman and administrator in the public area form the basis of his thoughts in his main work Il Giorno. The ideals defended by him in the framework of equality become valuable with the education of the members of society, and furthermore, contribute to the evolution of society. The aim of this article is to highlight the literary character and the structure of the ideals of Giuseppe Parini in relation to the different phases of his life. In addition, his interaction with different philosophers of the 18th century and his critical stance towards the nobility are examined. Parini who was in close contact with different important names of the Italian Enlightenment period succeded in preserving his distinct style. The outcome of his classical education-formation can be seen widely in his works