Interference Channel with Intermittent Feedback

We investigate how to exploit intermittent feedback for interference management. Focusing on the two-user linear deterministic interference channel, we completely characterize the capacity region. We find that the characterization only depends on the forward channel parameters and the marginal probability distribution of each feedback link. The scheme we propose makes use of block Markov encoding and quantize-map-and-forward at the transmitters, and backward decoding at the receivers. Matching outer bounds are derived based on novel genie-aided techniques. As a consequence, the perfect-feedback capacity can be achieved once the two feedback links are active with large enough probabilities.Comment: Extended version of the same-titled paper that appears in IEEE International Symposium on Information Theory (ISIT) 201

Usb Password Generator Berbasis ATMega8 Untuk Autentifikasi User

Semakin berkembangnya waktu, komputer sudah menjadi hal yang biasa dan mendarah daging. Kebanyakan dari seluruh aktivitas manusia menggunakan komputer dan dibantu komputer. Oleh karena hal itu, keamanan sangat diperlukan dalam pemakaian komputer dan kita biasanya akan mendengar kata password. Password sering membuat orang lebih sering melakukan kesalahan dikarenakan ingin membuat password yang panjang ataupun bermacam-macam. Disini penulis akan membuat suatu USB otomatis yang berisi password untuk autentikasi user

Comparision of uroflow parameters before and after hypospadias surgery

Aim: Uroflow investigation is used to identify whether stenosis has developed in the constituted neourethra after hypospadias repair. It is not clear whether a functional partial stenosis in the urethra in hypospadias cases is related to surgery or is present before the surgery. We aimed to investigate whether the obstructive pattern found in the urethra was related to the surgery or was present previously by performing a uroflow investigation before and after surgery in children operated for hypospadias and also in children with normal urethra as a control group in this study.Materials and methods: A total of 47 pediatric cases operated on and followed up with a diagnosis of hypospadias at the Ankara Child Health and Diseases, Hematology Oncology Training and Research Hospital’s Pediatric Surgery Clinic between January 2010 and June 2013 and a control group of 32 healthy children without symptoms of hypospadias or other urinary system problems were included in the study. Uroflowmetric investigations (maximum urine flow rate, mean urine flow rate, urination amount, urination duration, duration of reaching maximum speed) of the cases before and after surgery and uroflowmetric investigation of the control group together with the residual urine amount as examined by ultrasonography were compared. We evaluated 47 pediatric hypospadias cases in terms of age at surgery, meatus localization, type of surgery, and number of surgeries.Results: The mean age was 6.1 years for the patients operated with a diagnosis of hypospadias and 7.78 years for the control group. The most common uroflow flow curve in the preoperative study group and the control group was bell-type flow (57.4 and 43.8%). Bell-type flow was again most common postoperatively, but there was a significant decrease in plateau-type flow. Comparison of the uroflowmetry measurements of the hypospadias and control groups showed that the preoperative flow rates were low and some cases had residual urine in the bladder in the first group. When the postoperative measurements were used for the comparison, a significant difference was observed between the hypospadias and control groups in the flow rate and residual urine amount, whereas there was no difference compared with the preoperative evaluation. No significant relationship was found between the type of surgery used and uroflowmeter evaluations in our study.Conclusion: We found that the urination dynamics and partial urethral obstruction of hypospadias cases were present from the beginning and did not improve with surgery.Keywords: children, hypospadias, uroflowmetr

Force Modulating Dynamic Disorder: Physical Theory of Catch-slip bond Transitions in Receptor-Ligand Forced Dissociation Experiments

Recently experiments showed that some adhesive receptor-ligand complexes increase their lifetimes when they are stretched by mechanical force, while the force increase beyond some thresholds their lifetimes decrease. Several specific chemical kinetic models have been developed to explain the intriguing transitions from the "catch-bonds" to the "slip-bonds". In this work we suggest that the counterintuitive forced dissociation of the complexes is a typical rate process with dynamic disorder. An uniform one-dimension force modulating Agmon-Hopfield model is used to quantitatively describe the transitions observed in the single bond P-selctin glycoprotein ligand 1(PSGL-1)$-$P-selectin forced dissociation experiments, which were respectively carried out on the constant force [Marshall, {\it et al.}, (2003) Nature {\bf 423}, 190-193] and the force steady- or jump-ramp [Evans {\it et al.}, (2004) Proc. Natl. Acad. Sci. USA {\bf 98}, 11281-11286] modes. Our calculation shows that the novel catch-slip bond transition arises from a competition of the two components of external applied force along the dissociation reaction coordinate and the complex conformational coordinate: the former accelerates the dissociation by lowering the height of the energy barrier between the bound and free states (slip), while the later stabilizes the complex by dragging the system to the higher barrier height (catch).Comment: 8 pages, 3 figures, submitte

Spheres and Prolate and Oblate Ellipsoids from an Analytical Solution of Spontaneous Curvature Fluid Membrane Model

An analytic solution for Helfrich spontaneous curvature membrane model (H. Naito, M.Okuda and Ou-Yang Zhong-Can, Phys. Rev. E {\bf 48}, 2304 (1993); {\bf 54}, 2816 (1996)), which has a conspicuous feature of representing the circular biconcave shape, is studied. Results show that the solution in fact describes a family of shapes, which can be classified as: i) the flat plane (trivial case), ii) the sphere, iii) the prolate ellipsoid, iv) the capped cylinder, v) the oblate ellipsoid, vi) the circular biconcave shape, vii) the self-intersecting inverted circular biconcave shape, and viii) the self-intersecting nodoidlike cylinder. Among the closed shapes (ii)-(vii), a circular biconcave shape is the one with the minimum of local curvature energy.Comment: 11 pages, 11 figures. Phys. Rev. E (to appear in Sept. 1999

The impact of service quality on customer satisfaction and repurchase intention in the turkish banking sector: an analysis using structural equation modeling

Bu çalışma Türkiye’de özel bankalar tarafından sunulan hizmetlerin kalitesine yönelik müşteri beklentilerini ve algılarını değerlendirmeyi ve yapısal eşitlik modeli ile banka hizmet kalitesi, müşteri tatmini ve tekrar satın alma niyeti arasındaki ilişkiyi incelemeyi amaçlamaktadır. Araştırmada veri SERVQUAL ölçeği kullanılarak dünyanın en değerli 100 banka markası arasında yer alan özel bir bankanın 500 müşterisinden yüz yüze anket yöntemi ile toplanmıştır. Analiz sonuçları müşterilerin hizmet kalitesi algılamalarının beklentilerinin altında kaldığını ve en büyük farkın yanıt verebilirlik en küçük farkın ise somutluk boyutunda olduğunu ortaya koymaktadır. Ayrıca, kaliteli hizmet sunumunun müşterinin hizmeti tekrar satın alma niyetini doğrudan etkilemediği, buna karşın, müşteri tatminini artırarak müşterinin tekrar satın alma niyetini dolaylı ve güçlü bir şekilde etkilediğini göstermektedir. Bu sonuç müşteri tatmininin tekrar satın alma niyetine aracılık ettiğini doğrulamaktadır.The aim of this paper is two-fold: firstly, to assess customers’ expectations and perceptions towards the quality of services provided by private banks in Turkey and, secondly, to investigate the relationships between service quality, satisfaction, and repurchase intention for bank customers through a structural equation model. Data were collected by face to face interviews with 500 customers of a private bank listed in world’s most valuable 100 banking brands using the SERVQUAL method. Results revealed that customers’ perceptions of service quality fell short of their expectations, with the responsiveness dimension having the largest gap and the tangibles dimension having the smallest gap. Moreover, although the service quality did not have a direct effect on customer repurchase intention, it did have an indirect influence on customer repurchase intention via customer satisfaction. Results confirmed the mediator effect of customer satisfaction

Coiling Instabilities in Multilamellar Tubes

Myelin figures are densely packed stacks of coaxial cylindrical bilayers that are unstable to the formation of coils or double helices. These myelin figures appear to have no intrinsic chirality. We show that such cylindrical membrane stacks can develop an instability when they acquire a spontaneous curvature or when the equilibrium distance between membranes is decreased. This instability breaks the chiral symmetry of the stack and may result in coiling. A unilamellar cylindrical vesicle, on the other hand, will develop an axisymmetric instability, possibly related to the pearling instability.Comment: 6 pages, 2 figure