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Güç sistemlerindeki optimum otomatik gerilim regülasyonu için çoklu amaç fonksiyonunun belirlenmesi
No full textElektrik güç sistemlerinde sistem gerilimi, güç kalitesine etki eden en önemli parametrelerden biri olup çok
kritik bir öneme sahiptir. Güç sistemlerinde gerilim kontrolü otomatik gerilim regülatörleri (OGR) ile
yapılmaktadır. Otomatik gerilim regülatörleri, sistem geriliminin sabit tutulmasını sağlarlar. Bir OGR
sisteminde PID denetleyici parametrelerinin doğru bir şekilde belirlenmesi son derece önemlidir. Bu
parametrelerin en iyilerini bulma yöntemlerinden birisi de optimizasyon tekniklerini kullanmaktır. Amaç
fonksiyonu, optimizasyon algoritmalarının doğru yönlenmesi için kritik öneme sahiptir. Optimizasyon
tekniklerinde kullanılan amaç fonksiyonları genellikle ITSE, ITAE, ISE ve IAE’dir. Ancak en doğru sonuca
ulaşmak için amaç fonksiyonunun sisteme, probleme ve kısıtlara göre değişiklik göstermesi gerekmektedir.
Dolayısı ile optimizasyonun birden fazla amaç gözetilerek yapılması ihtiyacı ortaya çıkar. Kısıtlı bir süre
içerisinde otomatik gerilim regülatörleri için birden fazla amaç gözetilerek en iyi amaç fonksiyonunun elde
edilmesi, bir çok amaç fonksiyonlu optimizasyon problemini oluşturur. Bu bağlamda yapılan bu çalışmada,
bir OGR sisteminde optimal PID kazançlarının belirlenmesi için en iyi amaç fonksiyonunu bulma
amaçlanmıştır. Birden fazla amacı karşılamak amacıyla ortaya çıkan çok amaç fonksiyonlu optimizasyon
problemi, bu çalışma kapsamında belirlenen en uygun skalarizasyon tekniği ile birden fazla tek amaç
fonksiyonlu optimizasyon problemine indirgenmiş, indirgenen her bir problem ayrı ayrı eş zamanlı olarak
çözülmüştür. Çalışmada optimizasyon yöntemi olarak literatürde yaygın olarak bilinen PSO kullanılmıştır.
Belirlenen polinomal amaç fonksiyonunun literatürde yaygın olarak kullanılan 4 amaç fonksiyonuna göre çok daha iyi sonuçlar yakaladığı görülmüştür
A new approach for arrhythmia classification using deep coded features and LSTM networks
No full textBACKGROUND AND OBJECTIVE:
For diagnosis of arrhythmic heart problems, electrocardiogram (ECG) signals should be recorded and monitored. The long-term signal records obtained are analyzed by expert cardiologists. Devices such as the Holter monitor have limited hardware capabilities. For improved diagnostic capacity, it would be helpful to detect arrhythmic signals automatically. In this study, a novel approach is presented as a candidate solution for these issues.
METHODS:
A convolutional auto-encoder (CAE) based nonlinear compression structure is implemented to reduce the signal size of arrhythmic beats. Long-short term memory (LSTM) classifiers are employed to automatically recognize arrhythmias using ECG features, which are deeply coded with the CAE network.
RESULTS:
Based upon the coded ECG signals, both storage requirement and classification time were considerably reduced. In experimental studies conducted with the MIT-BIH arrhythmia database, ECG signals were compressed by an average 0.70% percentage root mean square difference (PRD) rate, and an accuracy of over 99.0% was observed.
CONCLUSIONS:
One of the significant contributions of this study is that the proposed approach can significantly reduce time duration when using LSTM networks for data analysis. Thus, a novel and effective approach was proposed for both ECG signal compression, and their high-performance automatic recognition, with very low computational cost
Characterization of viscoelastic properties of minced beef meat thawed by ohmic and conventional methods
No full textFrozen minced meat samples having fat contents of 2%, 10% and 18% were thawed using different methods (refrigeration thawing at ambient temperature of +4 ℃, under running cold water (+4 ℃) thawing, ohmic thawing for 10, 13 and 16 V/cm). Viscoelastic properties were determined by using rheological tests (oscillation and creep/recovery tests). Storage modulus, loss modulus, complex modulus, loss tangent, dynamic viscosity and complex viscosity values of minced meat samples increased as fat content increased. As frequency value increased, the modulus values of meat samples increased but dynamic and complex viscosity values of the samples decreased. The minced meat samples thawed by different methods had recoverable compliance values. The compliance values of meat samples during creep region can be well characterized by Burgers model. Ohmic thawing can be used as an alternative thawing method since it resulted in similar rheological properties of minced meat samples compared to refrigeration thawing at ambient temperature of +4 ℃ and under running cold water (+4℃) thawing
Micromorphological and anatomical investigation on six species of Onosma L. (Boraginaceae) from Turkey.
No full textMicromorphology and anatomy of six Onosma L. species, viz. O. argentata Hub.-
Mor., O. neglecta Riedl, O. proballanthera Rech. f., O. rechingeri Riedl, O. sericea
Willd. and O. stenoloba Hausskn. ex Riedl from Turky were investigated. Stem anatomy
revealed that cuticle layer ranged from 0.6 μm in O. argentata to 1.7 μm in O.
proballanthera. Parenchymatous cells of O. neglecta and O. stenoloba possessed more
intense starch than the other species studied. In leaf anatomy, the longest palisade
parenchyma was found in O. neglecta, while the smallest was noted in O. argentata.
Mesophyll structure of O. argentata, O. sericea and O. rechingeri was equifacial
(isobilateral), while O. neglecta, O. proballanthera and O. stenoloba presented bifacial
(dorsiventral) structure. Rugose nutlet ornamentation was observed in O. argentata, O.
neglecta and O. sericea, whereas reticulate type was found in O. proballanthera, O.
rechingeri and O. stenoloba. Onosma stenoloba could easily be distinguished from other
species by its aesterotrichous indumentum, and in contrary, other species possessed
haplotrichous type of indumentum. Micromorphological features of nutlet surface,
anatomical features of epidermal surface (trichomes and stomata), and lamina mesophyll
structure (dorsiventral and isobilateral) could be useful in solving taxonomic problem of
the genus
Yeni eğitim perspektifleri ve eğitimde yaratıcılık
No full textGelişen ve değişen dünyamızda yeni eğitim yaklaşımlarını dillendirmeye çalışan bir yazı
Synthesis, characterization and spectroscopic investigation of N-(2-acetylbenzofuran-3-yl)acrylamide monomer: Molecular structure, HOMO–LUMO study, TD-DFT and MEP analysis
No full textIn this study, a novel acrylamide monomer was synthesized and characterized by UV-Vis, FT-IR and 1H
NMR measurements. The acrylamide monomer namely, N-(2-acetyl-benzofuran-3-yl)acrylamide
(NABA), was prepared in two steps. In the first step, 1-(3-aminobenzofuran-2-yl)ethan-1-one was synthesized by the reaction of 1-chloroacetone with 2-hydroxy-benzonitrile under basic conditions. In the
second step, the obtained 1-(3-aminobenzofuran-2-yl)ethan-1-one was reacted with acryloyl chloride
and triethylamine at 0e5 C temperature for obtaining NABA monomer. Then, the structural, vibrational,
nuclear magnetic resonance and electronic properties for the synthesized monomer were determined by
quantum chemical calculations of DFT method. The results were compared with experimental FT-IR, 1H
NMR and UVeVis spectral data. The band gap of HOMO and LUMO show that the NABA monomer is
chemically active and has charge transfer within the monomer. Moreover, molecular electrostatic potential (MEP) maps were drawn to identify reactive regions of NABA monomer
Using Box–Behnken design approach to investigate benzo[a]anthracene formation in smoked cattle meat samples and its’ risk assessment
No full textIn present study, a novel approach was selected for benzo[a]anthracene determination from smoked cattle meat samples using solid phase extraction under various experimental conditions. To optimize experimental variables, a three factor, three-level Box–Behnken experimental design combining with response surface methodology and quadratic programming were employed to prevent excessive amount of benzo[a]anthracene formation in smoked meat based on different experimental parameters. The influence of some important process parameters including cooking time (10–30 min), fat ratio (5–25%) and distance to the cooking source (5–25 cm), which significantly affected the formation efficiency of benzo[a]anthracene were optimized. The analysis of variance was conducted for specifying the interactions of independent variables. The independent and the dependent variables interactions were investigated. The quadratic regression model and the response surface contour plots were used to determine optimum values for the selected variables. The results of study revealed that optimum cooking time of smoked cattle meat was determined as 24.9 min, fat ratio 7.9% and the distance to the cooking source 21.8 cm. Under optimum conditions, minimum benzo[a]anthracene was formed in meat and its amount was determined using high performance liquid chromatography-mass spectrophotometer as qualitative and quantitative. The limit of detection and limit of quantitation values were calculated as 0.4 µg kg−1 and 1.1 µg kg−1, respectively
Meslek Yüksekokulu Öğrencilerinin Sanal Kimlik Algısı ve Toplumsal Yabancılaşma Durumlarının İncelenmesi
No full textGünümüz teknolojisinde yaşanan gelişmelerle birlikte sosyal medya olarak adlandırılan yeni bir ortam,
günlük yaşam içinde yerini hızla almaya başlamıştır. Özellikle mobil iletişim teknolojilerinin
hayatımıza girmesiyle birlikte insanlar kendi öz kimliklerinin dışında farklı kimlik tasarımları
oluşmaya başlamış, sahip olduğu sosyal yaşamdan uzaklaşarak, sosyalleşme aracı olarak gördükleri
makineye bağımlı hale gelmiştir. Yaşanan bu değişimler en çok yeni nesil tarafından benimsenir
olmuştur. Bu çalışma ile Meslek Yüksekokullarında öğrenim gören öğrencilerin sanal kimlik algısı ve
toplumsal yabancılaşma durumları incelemeye değer görülmüştür. Araştırma nitel araştırma
paradigması doğrultusunda şekillendirilmiştir. Araştırma verileri yarı yapılandırılmış görüşme formu
ile toplanmış, veriler içerik analizi yöntemi ile analiz edilmiştir. Yapılan analizler sonucunda elde
edilen bulgulara ve bu bulgular doğrultusunda ortaya çıkan sonuçlara, tartışmaya ve önerilere ayrıca
yer verilecekti
Olimpos Yeni Bir Yaşam Tarzı
No full textBilim kurgunun felsefeyle buluştuğu ve yeni bir yaşam tarzına dönüştüğü eser. İnsanlığı en az bin sene daha yer küremizde yaşatabilecek kurguların tasarlandığı kurgu-gerçek arası çalışma
Determination of Antioxidant Capacity using Different Acidified Solvents and Element Contents of Allium Tuncelianum: A Regional and Varietal Study on Endemic Edible Garlic
No full textAllium tuncelianum (Tunceli garlic), an endemic and threatened plant species in the Tunceli province of Eastern Turkey, is an important native source for local people. The antioxidant activities of the acidified extracts of water, acetonitrile, methanol, and ethanol of Allium tuncelianum were investigated using five antioxidant capacity tests. The results indicated that methanol extract efficiencies of garlic samples using the ABTS, CUPRAC, and reducing power capacities were higher than the other extracts. Water extract and acetonitrile extract values were highest for total phenolic content and metal chelating activities, respectively. Moreover, the element contents such as calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), and zinc (Zn) of Allium tuncelianum samples digested by microwave and ashing ovens were determined by flame atomic absorption spectrophotometry and the results were compared statistically. The Ca, Cu, K, Mg, and Zn concentrations using the microwave method were found to be higher than the ashing procedure. However, the Fe, Mn, and Na concentrations using the ashing method were found to be higher than those using the the microwave protocol