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8. On the Optimal Achievable Rates for Linear Computation With Random Homologous Codes

Author

Sen, Pinar, Lim, Sung Hoon, and Kim, Young-Han

Subjects
Computer Science - Information Theory
Abstract

The problem of computing a linear combination of sources over a multiple access channel is studied. Inner and outer bounds on the optimal tradeoff between the communication rates are established when encoding is restricted to random ensembles of homologous codes, namely, structured nested coset codes from the same generator matrix and individual shaping functions, but when decoding is optimized with respect to the realization of the encoders. For the special case in which the desired linear combination is "matched" to the structure of the multiple access channel in a natural sense, these inner and outer bounds coincide. This result indicates that most, if not all, coding schemes for computation in the literature that rely on random construction of nested coset codes cannot be improved by using more powerful decoders, such as the maximum likelihood decoder. The proof techniques are adapted to characterize the rate region for broadcast channels achieved by Marton's (random) coding scheme under maximum likelihood decoding.

Published
2018

9. Homologous Codes for Multiple Access Channels

Author

Sen, Pinar and Kim, Young-Han

Subjects
Computer Science - Information Theory
Abstract

Building on recent development by Padakandla and Pradhan, and by Lim, Feng, Pastore, Nazer, and Gastpar, this paper studies the potential of structured nested coset coding as a complete replacement for random coding in network information theory. The roles of two techniques used in nested coset coding to generate nonuniform codewords, namely, shaping and channel transformation, are clarified and illustrated via the simple example of the two-sender multiple access channel. While individually deficient, the optimal combination of shaping and channel transformation is shown to achieve the same performance as traditional random codes for the general two-sender multiple access channel. The achievability proof of the capacity region is extended to the multiple access channels with more than two senders, and with one or more receivers. A quantization argument consistent with the construction of nested coset codes is presented to prove achievability for their Gaussian counterparts. These results open up new possibilities of utilizing nested coset codes with the same generator matrix for a broader class of applications.

Published
2018

28. A Low-Complexity Graph-Based LMMSE Receiver for MIMO ISI Channels with M-QAM Modulation

Author

Sen, Pinar and Yilmaz, Ali Ozgur

Subjects
Computer Science - Information Theory
Abstract

In this paper, we propose a low complexity graph-based linear minimum mean square error (LMMSE) equalizer in order to remove inter-symbol and inter-stream interference in multiple input multiple output (MIMO) communication. The proposed state space representation inflicted on the graph provides linearly increasing computational complexity with block length. Also, owing to the Gaussian assumption used in the presented cycle-free factor graph, the complexity of the suggested equalizer structure is not affected by the size of the signalling space. In addition, we introduce an efficient way of computing extrinsic bit log-likelihood ratio (LLR) values for LMMSE estimation compatible with higher order alphabets which is shown to perform better than the other methods in the literature. Overall, we provide an efficient receiver structure reaching high data rates in frequency selective MIMO systems whose performance is shown to be very close to a genie-aided matched filter bound through extensive simulations., Comment: 28 pages, 6 figures, 2 tables, submitted to IEEE Transactions on Wireless Communications

Published
2014
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29. Factor Graph Based LMMSE Filtering for Colored Gaussian Processes

Author

Sen, Pinar and Yilmaz, Ali Ozgur

Subjects
Computer Science - Information Theory
Abstract

We propose a low complexity, graph based linear minimum mean square error (LMMSE) filter in which the non-white characteristics of a random process are taken into account. Our method corresponds to block LMMSE filtering, and has the advantage of complexity linearly increasing with the block length and the ease of incorporating the a priori information of the input signals whenever possible. The proposed method can be used with any random process with a known autocorrelation function with the help of an approximation to an autoregressive (AR) process. We show through extensive simulations that our method performs very close to the optimal block LMMSE filtering for Gaussian input signals., Comment: 5 pages, 4 figures

Published
2014

30. A Low-Complexity Graph-Based LMMSE Receiver Designed for Colored Noise Induced by FTN-Signaling

Author

Sen, Pinar, Aktas, Tugcan, and Yilmaz, A. Ozgur

Subjects
Computer Science - Information Theory
Abstract

We propose a low complexity graph-based linear minimum mean square error (LMMSE) equalizer which considers both the intersymbol interference (ISI) and the effect of non-white noise inherent in Faster-than-Nyquist (FTN) signaling. In order to incorporate the statistics of noise signal into the factor graph over which the LMMSE algorithm is implemented, we suggest a method that models it as an autoregressive (AR) process. Furthermore, we develop a new mechanism for exchange of information between the proposed equalizer and the channel decoder through turbo iterations. Based on these improvements, we show that the proposed low complexity receiver structure performs close to the optimal decoder operating in ISI-free ideal scenario without FTN signaling through simulations., Comment: 6 pages, 6 figures, IEEE Wireless Communications and Networking Conference 2014, Istanbul, Turkey

Published
2013
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36. Insight into a rift volcanism with the petrogenesis of ultramafic enclaves and the host basalts: Kula Volcanic Field, Western Anatolia, Turkey

Author

Şen, Erdal, Aydar, Erkan, Şen, Pınar, Gourgaud, Alain, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)

Subjects
ultramafic enclaves, fractional crystallisation, uplift, partial melting, alkaline basalt, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology
Abstract

International audience; The Quaternary Kula Volcanic Field (KVF), located on an E-W trending Plio-Quaternary horst, consists of at least 80 scoria cones, associated fissural lava flows and maars. Volcanic activity is divided into three main stages as BI (ca. 2-0.9 Ma), BII (ca. 300-50 ka) and BIII (ca. 10-0.7 ka). The volcanic products of BII and BIII contain ultramafic enclaves. They are generally spherical or elliptical varying in size from 1.3), Nb/Y (>1.7), and Nb/U (>31) ratios, reflecting that crustal contamination is insignificant. Petrogenetic modelling shows that Kula enclaves and host rocks are probably originating from 3-5% partial melting of garnet and spinel-peridotite mantle source mixtures. Rb/Sr (0.03-0.10) and slightly high Ba/Rb (9.5-23) ratios for host rocks demonstrate the presence of amphibole and phlogopite in their source, while low Rb/Sr (0.01-0.09) and high Ba/Rb (18-115) reveal that amphibole is present in the source. Estimated T/P conditions of early crystallizations are between 19.5–9.5 kbar, 63–31 km, and 1260–1130 °C for host rocks and 18.3–11.1 kbar, 59–36 km, and 1324–1208 °C for the enclaves, which suggests that the crystallization might have taken place in the lithospheric mantle.

Published
2023
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41. İmmünsüpresif hastalarda HBV reaktivasyonunun önlenmesi için tenofovir alafenamid profilaksisi: Çok merkezli bir çalışma

Author

SENOL, Sebnem, SÖNMEZ, Ufuk, DEMİRDAL, Tuna, ŞEN, Pınar, TÜRK, Deniz, ATALAY, Sabri, AKYOL, Deniz, MERMUTLUOĞLU, Çiğdem, ÇELEN, Mustafa Kemal, YAMAZHAN, Tansu, PULLUKÇU, Hüsnü, Dicle Üniversitesi, Tıp Fakültesi, Dahili Tıp Bilimleri Bölümü, Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Ana Bilim Dalı, Mermutluoğlu, Çiğdem, Çelen, Mustafa Kemal, and Yamazhan, Tansu

Subjects
Tenofovir alafenamid, Medicine, İmmünsüpresif ajanlar, Tenofovir alafenamide, Immunosuppressive agents, tenofovir alafenamide,Hepatitis B / prevention & control,Immunosuppressive Agents, Hepatitis B prevention and control, tenofovir alafenamid,Hepatit B / önlem ve kontrol,immunsüpresif ajanlar, Tıp, Hepatit B önlem ve kontrol
Abstract

Amaç: İmmünsupresif tedavi altındaki yüksek riskli hastalarda hepatit B reaktivasyonu antiviral profilaksi ile önlenebilir. Antiviral seçiminde entekavir (ETC) veya tenofovir disoproksil fumarat (TDF) uzun zamandır kullanılabilmekteyken yakın zamanda kullanıma giren tenofovir alafenamid (TAF) güvenli yan etki profili ile iyi bir alternatif olmuştur. Bu çok merkezli geniş hasta sayılı çalışmada immünsüpresif hasta grubunda tenofovir alafenamidin (TAF) etkinliği ve güvenliği araştırılmıştır. Gereç ve Yöntem: Altı eğitim ve araştırma hastanesinin 1 Ocak 2019- 30 Eylül 2021 arasındaki kayıtları retrospektif olarak incelenerek immünsüpresif tedavi altında iken hepatit B için antiviral profilaksi başlanan ve en az 6 ay süre ile takip edilen hastalar çalışmaya dahil edilmiştir. Aldıkları immünsüpresif tedavi veya kemoterapiye ayrıca hepatit B serolojilerine göre risk grupları belirlenmiş, hepatit B reaktivasyon varlığı ve yan etkileri yönünden incelenmiştir. Bulgular: Yaş ortalaması 62.5±29 yıl olan 148 hastanın 85’i (%57.4) TAF, 63’ü (%42.6) tenofovir disoproksil fumarate (TDF) veya entekavir (ETC) ile profilaksi almaktaydı. %83.1’i HBsAg (-) antiHBc (+) %16.9’u HBsAg (+) olarak bulundu; kronik HBV’li hastaların %36 sının HBV DNA’sı saptanabilir düzeyin üzerindeydi. Çoğu (%69.6) hematolojik bir malinite nedeni ile immünsüpresif alırken %89.2’sinin aldığı tedavi yüksek riskli ilaç grubunda idi. Riskler açısından TAF ve diğer tedavileri alanlar arasında farklılık yoktu. Tedavi gruplarının hiçbirinde reaktivasyon ya da yan etkiye rastlanmadı.Sonuç: Kronik HBV tedavisinde olduğu gibi immünsüpresif tedavi alan bireylerde HBV reaktivasyonunun önlenmesinde de TAF en az TDF ve ETC kadar etkindir. TDF nin böbrek ve kemik yan etkilerinin TAF da görülmemesinin etkin ve güvenli bu tedavi seçeneğini immünsüpresif hastalarda öne çıkaracağını düşünmekteyiz., Purpose: Reactivation of hepatitis B may be prevented by antiviral therapy in immunosuppressed high risk patients. Entecavir (ETC) and tenofovir disoproksil fumarat (TDF) have been used for a long time and recently introduced tenofovir alafenamid (TAF) seems to be a good alternative with rare side effects. This multicentered study with a large patient population aimed to investigate the effectiveness of tenofovir alafenamid (TAF) in immunsuppressed subjects. Materials and Methods: The records of six training and research hospitals between January 1, 2019 and September 30, 2021 were retrospectively reviewed, and patients who were started antiviral prophylaxis for hepatitis B and followed up for at least 6 months while under immunosuppressive therapy were included in the study. Risk groups were determined according to the immunosuppressive treatment or chemotherapy they received, as well as hepatitis B serology, and were examined in terms of the presence of hepatitis B reactivation and its side effects.Results: The mean age of patients was found as 62.5±29. Out of 148 patients, 85 (57.4%) received TAF, 63 (42.6%) received either Entecavir (ETC) or tenofovir disoproksil fumarat (TDF). The majority (83.1%) was found as HBsAg (-) antiHBc (+) and 16.9% was HBsAg (+). HBV DNA was traced in 36% of chronic HBV patients. Most of the patients (69.6%) were receiving immunospuppressives for treatment of a haematologic malignancy and 89.2% was in the high risk treatment group. There was no difference between TAF and the other drugs in terms of risks. Reactivation was not seen in any of the treatment groups. Conclusion: TAF is as effective as TDF and ETC when used for prophylaxis in immunosuppressed HBV patients. Side effects on kidney and bone are not seen in TAF treatment groups which will probably play a role in preferring this new drug.

Published
2022

45. The Epidemiology, Clinical Manifestations, Radiology, Microbiology, Treatment, and Prognosis of Echinococcosis: Results of NENEHATUN Study

Author

Parlak, Emine, primary, Kerget, Ferhan, additional, Demirdal, Tuna, additional, Şen, Pınar, additional, Ulaş, Ali Bilal, additional, Öztürk Durmaz, Şenay, additional, Pekok, Umut, additional, Ertürk, Ayşe, additional, Akyol, Deniz, additional, Kepenek Kurt, Esma, additional, Köksal Alay, Handan, additional, Pullukçu, Hüsnü, additional, Taşbakan, Meltem, additional, Erol, Serpil, additional, Laloğlu, Esra, additional, Öztürk Engin, Derya, additional, Ağalar, Canan, additional, and Parlak, Mehmet, additional

Published
2021
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46. 4- (4-formilfenoksi) ftalonitrilin 4- (4-karboksilfenoksi) ftalonitril'e Ortam Koşullarında Oksidasyonu

Author

Şen, Pınar, Demirtaş, Güneş, Avcı, Davut, Yıldız, Salih Zeki, and OMÜ

Subjects
Mühendislik, Crystal structure, İnşaat Mühendisliği, Kimya, Gıda Bilimi ve Teknolojisi, law.invention, Phthalonitrile, chemistry.chemical_compound, theoretical calculation, law, Makine, Tıbbi, Crystallization, lcsh:Science, Partiküller ve Alanlar, Matematik, Bilgi Sistemleri, Hydrogen bond, Temel Bilimler, Fizikokimya, Nükleer, Organik, General Medicine, Biyoloji Çeşitliliğinin Korunması, Analitik, Biyoloji, Katı Hal, crystal structure, oxidation, Fizik, Jeoloji, Triclinic crystal system, Substituted phthalonitrile,Crystal structure,Oxidation,Theoretical calculation, Uygulamalı, Nucleophilic substitution, Molecule, Bilgisayar Bilimleri, lcsh:Science (General), Basic Sciences, substituted phthalonitrile, Akışkanlar ve Plazma, Crystallography, Çevre Mühendisliği, chemistry, lcsh:TA1-2040, Phthalocyanine, lcsh:Q, lcsh:Engineering (General). Civil engineering (General), Atomik ve Moleküler Kimya, lcsh:Q1-390
Abstract

The substituted phthalonitriles have been used to prepare soluble phthalocyanine species in recent years. One of the most used phthalonitrile derivatives for the target product is 4-nitrophthalonitrile. In this study 4-(4-formylphenoxy) phthalonitrile was prepared as the substituted phthalonitrile derivative by the nucleophilic substitution reaction of para-hydroxybenzaldehyde with 4-nitrophthalonitrile. During the crystallization of the product by slow evaporation technique, it readily self-oxidized to 4-(4-carboxylphenoxy) phthalonitrile at ambient condition open to air. The crystal structure of the molecule was determined by XRD technique. The molecule crystalizes at triclinic space group P-1 and the unit cell parameters of crystal are a6.3591 (10) Å, b7.5464 (11) Å, c13.819 (2) Å, ?88.434 (11), ?87.942 (12), ?80.111 (12) and Z2. The crystal structure has intermolecular O?HO, C?HN and C?HO hydrogen bonds. In addition to these hydrogen bonds, C—NCg and CgCg interactions are present between molecules. In the crystal, intermolecular O?HO hydrogen bonds occur between molecular units in a dimeric molecular form. Molecular structure, vibrational frequencies and 1H and 13C NMR chemical shifts of the target compound have been calculated by using B3LYP method with 6-311G(d, p) basis set, as well. Sübstitüe ftalonitriller, son yıllarda çözünür ftalosiyanin türlerini hazırlamak için kullanılmaktadır. Hedef ürün için en çok kullanılan ftalonitril türevlerinden biri, 4-nitroftalonitrildir. Bu çalışmada, 4-(4-formilfenoksi) ftalonitril, para-hidroksibenzaldehidin 4-nitroftalonitril ile nükleofilik yerdeğiştirme reaksiyonu ile sübstitüe ftalonitril türevi olarak hazırlanmıştır. Ürün yavaş buharlaştırma tekniği ile kristallendirilmesi sırasında, havaya açık ortam koşullarında, 4- (4-karboksilfenoksi) ftalonitril'e kendiliğinden oksitlenmiştir. Molekülün kristal yapısı XRD tekniği ile belirlendi. Molekül, triklinik uzay grubu P-1'de kristallenmiştir ve kristalin birim hücre parametreleri a 6.3591 (10) Å, b 7.5464 (11) Å, c 13.819 (2) Å, a 88.434 (11) , 87 87.942 (12) , ? 80.111 (12) ve Z 2’ dir. Kristal yapı moleküllerarası O ? H O, C ? H N ve C ? H O hidrojen bağlarına sahiptir. Bu hidrojen bağlarına ek olarak, moleküller arasında C — N Cg ve Cg Cg etkileşimleri mevcuttur. Kristalde moleküllerarası O ? H O hidrojen bağları, bir dimerik yapı içinde moleküler birimler arasında meydana gelir. Hedef bileşiğin, moleküler yapısı, titreşim frekansları ve 1H ve 13C NMR kimyasal kaymaları da 6-311 G (d, p) temel seti ile B3LYP metodu kullanılarak hesaplanmıştır.

Published
2019
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48. Pnömokok İnfeksiyonlarının Klinik Özellikleri ve İnvazif Hastalık Göstergeleri.

Author

Şen, Pınar, Demirdal, Tuna, and Nemli, Salih Atakan

Subjects
*BRAIN abscess, *PERITONITIS, *PYELONEPHRITIS, *PERICARDITIS, *MORTALITY, *WOUND infections, *TIME, *STREPTOCOCCAL diseases, *RETROSPECTIVE studies, *DISEASES, *ENDOCARDITIS, *SEPSIS, *DEMOGRAPHY, *MENINGITIS, *ARTHRITIS, *DISEASE risk factors
Abstract

Clinical Characteristics of Pneumococcal Infections and Predictors of Invasive Pneumococcal Disease [ABSTRACT FROM AUTHOR]

Published
2022
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50. COVID-19 İnfeksiyonunda Mayıs-Ağustos 2020 Döneminde Yoğun Bakıma Yatış ve Mortalite ile İlişkili Faktörler.

Author

Şen, Pınar and Demirdal, Tuna

Subjects
*INTENSIVE care units, *COVID-19, *MYALGIA, *PATIENTS, *RETROSPECTIVE studies, *HOSPITAL admission & discharge, *RISK assessment, *DYSPNEA
Abstract

Objective: COVID-19 infection causes severe pneumonia and multi-organ failure in adults, increases morbidity and mortality. Our study aimed to determine the factors affecting intensive care unit admission and mortality in hospitalized COVID-19 patients. Methods: The demographic, clinical, and laboratory data of hospitalized patients due to COVID-19 between May 1, 2020 and August 1, 2020 were evaluated retrospectively. Patients who were admitted to the intensive care unit or died during follow-up were included in the study group, and patients who were followed in the inpatient settings and survived consisted the control group. The data obtained at the time of hospitalization were evaluated statistically. Results: A total of473 patients were included in the study. The median age of the patients was 53 years (40-68 years), and 269 (56.9%) were male. During the follow-up, 93(19.7%) patients were admitted to the intensive care unit (ICU). Of the 468 patients for whom follow-up data were available, 62(13.2%) patients died. Patients with older age and comorbid diseases had higher ICU admission and mortality rates (p<0.001 and p<0.001). ICU admission rate was higher in patients with cough (p=0.002), myalgia (p=0.016), and dyspnea (p<0.001) during hospital admission. At the same time, dyspnea was more common in patients who died (p<0.001), and myalgia was more common in surviving patients (p=0.020). Laboratory values associated with both ICU admission and mortality were glucose (p<0.001, p<0.001), AST (p<0.001, p<0.001), serum creatinine (p<0.001, p<0.001), direct bilirubin (p<0.001, p=0.009), albumin (p<0.001, p<0.001), CRP (C-reactive protein) (p<0.001, p<0.001), procalcitonin (p<0.001, p<0.001), leukocyte count (p<0.001, p<0.001), lymphocyte count (p<0.001, p<0.001), neutrophil count (p=0.007, p<0.001), hemoglobin (p<0.001, p<0.001), troponin (p<0.001, p<0.001), D-dimer (p<0.001, p<0.001), ferritin (p<0.001, p<0.001) prothrombin time (p<0.001, p<0.001) and INR (international normalized ratio) (p<0.001, p<0.001) levels. Conclusions: Determining the parameters that define high-risk COVID-19 infected patients in the early period can contribute to reduce ICU admissions and mortality by improving patient management and resource utilization in hospitals. [ABSTRACT FROM AUTHOR]

Published
2022
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