Behavioral Mimicry Covert Communication

Covert communication refers to the process of communicating data through a channel that is neither designed, nor intended to transfer information. Traditionally, covert channels are considered as security threats in computer systems and a great deal of attention has been given to countermeasures for covert communication schemes. The evolution of computer networks led the communication community to revisit the concept of covert communication not only as a security threat but also as an alternative way of providing security and privacy to communication networks. In fact, the heterogeneous structure of computer networks and the diversity of communication protocols provide an appealing setting for covert channels. This dissertation is an exploration on a novel design methodology for undetectable and robust covert channels in communication networks. Our new design methodology is based on the concept of behavioral mimicry in computer systems. The objective is to design a covert transmitter that has enough degrees of freedom to behave like an ordinary transmitter and react normally to unpredictable network events, yet it has the ability to modulate a covert message over its behavioral fingerprints in the network. To this end, we argue that the inherent randomness in communication protocols and network environments is the key in finding the proper medium for network covert channels. We present a few examples on how random behaviors in communication protocols lead to discovery of suitable shared resources for covert channels. The proposed design methodology is tested on two new covert communication schemes, one is designed for wireless networks and the other one is optimized for public communication networks (e.g., Internet). Each design is accompanied by a comprehensive analysis from undetectability, achievable covert rate and reliability perspectives. In particular, we introduced turbo covert channels, a family of extremely robust model-based timing covert channels that achieve provable polynomial undetectability in public communication networks. This means that the covert channel is undetectable against any polynomial-time statistical test that analyzes samples of the covert traffic and the legitimate traffic of the network. Target applications for the proposed covert communication schemes are discussed including detailed practical scenarios in which the proposed channels can be implemented

Time Response of a Resonant Tunneling Diode Based Photo- Detector (RTD-PD)

در این مقاله ، یک دیود تونل زنی تشدید با ساختار سد مضاعف AlAs / GaAs با استفاده از عملکرد سبز غیر تعادلی شبیه سازی شده است. یک لایه جذب InGaAs منطبق شده برای تشخیص نور در طول موج λ = 600 نانومتر به دستگاه اضافه می شود . میدان الکتریکی از طریق دستگاه و مشخصات نمودار باند انرژی ارائه شده است. جریان عکس دستگاه و منحنی های جریان جریان منبع در مقابل شدت نور مقایسه می شوند . در دمای اتاق ، بازده کوانتومی 95/0 برای دستگاه بدست آمد . پاسخ زمان گذرا دستگاه به دست آمد و وابستگی آن به پارامترهای ساختاری (ضخامت لایه جذب ، ضخامت کلکتور و انتشار دهنده ودوپینگ مخاطبین) ، شدت نور ، زاویه نور ساطع شده و سوگیری ولتاژ شبیه سازی شده و تأثیر آنها بر عملکرد دستگاه مورد تجزیه و تحلیل قرار گرفت. پهنای باند دستگاه به دست آمد. نتایج شبیه سازی نشان می دهد که وقتی بایاس ولتاژ افزایش یابد ، زمان افتادن کاهش می یابد و پاسخ دستگاه سریعتر است. با تغییر ضخامت لایه جذب و مخاطب ، پاسخ زمان RTD-PD تغییر می کند. تغییرات دوپینگ در لایه های تماس بر روی پهنای باند تأثیر می گذارد. نتیجه نشان می دهد که تغییرات شدت نور و زاویه نور ساطع شده ، پاسخ زمان گذرا را تغییر می دهند

Prevalence and Predictors of Domestic-Violence towards Wives by their Psychiatric Hospitalized Husbands

Objective: Violence imposed on wives by their inpatient psychiatric husbands has not been studied yet. The current study surveyed the rates and predictors of violence committed by inpatient psychiatric husbands towards their wives. Methods: A convenient sample of wives of 209 married male psychiatric inpatients completed a self-reported questionnaire. They were asked about physical, emotional, social and economic abuse. Results: More than 80% of the husbands socially abused their wives; 73.0% of the wives had been regularly beaten by their husbands; the rate for humiliation was 77.2%; and only 14.1% of the wives reported that their sexual relationship with their husbands is with desire. Conclusion: There is a dramatic high rate of different types of abuse toward wives by their inpatient psychiatric husbands. They are commonly victimized by their husbands. Moreover, different types of violence always co-occur.  Future studies should consider this important issue which is unfortunately an ignored research area

The effects of dietary supplements in patients with cervical cancer: a comprehensive systematic review

Background: Recent studies reported that complementary therapy including dietary supplements may has a beneficial role in cervical cancer. However, the results are inconsistent. This study aimed to investigate the association between cervical cancer and dietary supplements. Methods: A systematic literature review was conducted to summarize and quantify the most recent findings on dietary supplement and cervical cancer. Several databases were checked for relevant publications published in English up to March 2023. Of the 32 articles identified, only 20 met the inclusion criteria and were included. Results: Women with cervical intraepithelial neoplasia may benefit from folate supplementation against oxidative stress and inflammation. Vitamin D may reduce oxidative stress and may have a therapeutic effect. Zinc promotes the clearance of the human papilloma virus and reduces the chance of viral infection. The use of probiotic supplements may improve the complications associated with chemotherapy in patients with cervical cancer, such as diarrhea and abdominal pain. Radiotherapy and chemotherapy complications may also be reduced by omega-3 fatty acids. Conclusion: Some dietary supplements including folate, vitamin D, zinc, probiotics, and omega-3 fatty acids may have beneficial effects in patients with cervical cancer. Further studies are warranted to confirm these results

Biomimetic amniotic/silicone-based bilayer membrane for corneal tissue engineering

Amniotic membrane (AM) is an effective and widely used dressing in ocular injuries to reconstruct the cornea. Due to its low mechanical strength, high biodegradation rate, and difficult handling, its usage in medical interventions remains challenging. In this study, decellularized AM was covered with an ultrathin layer of Polydimethylsiloxane (PDMS) through a spinning method, which in turn resulted in an ultrathin (less than 80 µm in thickness) bilayer corneal wound dressing membrane with improved mechanical behavior and transparency. The biomechanical, biological, and antibacterial properties of the bilayer membranes were measured both in vitro and in vivo. The optimized microsized membrane was applied on a corneal defect wound created in a rabbit model to evaluate the corneal healing. The results demonstrated a significant decrease in degradation rate, improved mechanical properties, and AM/PDMS transparency compared with AM. The corneal transparency improved until 21 days post-surgery in AM/PDMS group. Histological evaluations revealed that AM/PDMS had better epithelial delaminated cell morphology. The results of the RT-PCR showed a significant increase in MMP9, a significant decrease in Col1A1, TGF-β1, TNF-α and IL-6 in both AM and AM/PDMS compared with control wounds. This study suggessts AM/PDMS membrane as an excellent corneal wound dressing