54 research outputs found

    An architecture framework for enhanced wireless sensor network security

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    This thesis develops an architectural framework to enhance the security of Wireless Sensor Networks (WSNs) and provides the implementation proof through different security countermeasures, which can be used to establish secure WSNs, in a distributed and self-healing manner. Wireless Sensors are used to monitor and control environmental properties such as sound, acceleration, vibration, air pollutants, and temperature. Due to their limited resources in computation capability, memory and energy, their security schemes are susceptible to many kinds of security vulnerabilities. This thesis investigated all possible network attacks on WSNs and at the time of writing, 19 different types of attacks were identified, all of which are discussed including exposures to the attacks, and the impact of those attacks. The author then utilises this work to examine the ZigBee series, which are the new generation of wireless sensor network products with built-in layered security achieved by secure messaging using symmetric cryptography. However, the author was able to uniquely identify several security weaknesses in ZigBee by examining its protocol and launching the possible attacks. It was found that ZigBee is vulnerable to the following attacks, namely: eavesdropping, replay attack, physical tampering and Denial of Services (DoS). The author then provides solutions to improve the ZigBee security through its security schema, including an end-to-end WSN security framework, architecture design and sensor configuration, that can withstand all types of attacks on the WSN and mitigate ZigBee’s WSN security vulnerabilities

    Impact of Encryption on Qos in Voip

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    This paper studies the impact of different encryption algorithms on the quality of Voice over Internet Protocol (VoIP). Assuring Quality of Service (QoS) is one of the primary issues in any IP based application that examines the voice quality of VoIP. This paper examines QoS in terms of lost packet ratio, latency and jitter using different encryption algorithms along with firewalling at the IP layer. The results of laboratory tests indicate that the impact on the overall performance of VoIP depends upon the bandwidth available and encryption used. Findings include the need for the provision of bandwidth for encryption, and even when adequate bandwidth is provided encryption algorithms can increase lost packet ratios and packet latency, and reduce.Overall, the results indicate the implementation of encryption algorithms may degrade the voice quality even if bandwidth is adequate

    VoIP: Making Secure Calls and Maintaining High Call Quality

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    Modern multimedia communication tools must have high security, high availability and high quality of service (QoS). Any security implementation will directly impact on QoS. This paper will investigate how end-to-end security impacts on QoS in Voice over Internet Protocol (VoIP). The QoS is measured in terms of lost packet ratio, latency and jitter using different encryption algorithms, no security and just the use of IP firewalls in Local and Wide Area Networks (LAN and WAN). The results of laboratory tests indicate that the impact on the overall performance of VoIP depends upon the bandwidth availability and encryption algorithm used. The implementation of any encryption algorithm in low bandwidth environments degrades the voice quality due to increased loss packets and packet latency, but as bandwidth increases encrypted VoIP calls provided better service compared to an unsecured environment.Les eines modernes de comunicació multimèdia han de tenir alta seguretat, alta disponibilitat i alta qualitat de servei (QoS). Cap tipus d¿implementació de seguretat tindrà un impacte directe en la qualitat de servei. En aquest article s¿investiga com la seguretat d'extrem a extrem impacta en la qualitat de servei de veu sobre el Protocol d'Internet (VoIP). La qualitat de servei es mesura en termes de pèrdua de proporció de paquets, latència i jitter utilitzant diferents algoritmes d¿encriptació, sense seguretat i només amb l'ús de tallafocs IP en local i en xarxes d'àrea àmplia (LAN i WAN). Els resultats de les proves de laboratori indiquen que l'impacte general sobre el rendiment de VoIP depèn de la disponibilitat d'ample de banda i l'algorisme de xifrat que s'utilitza. La implementació de qualsevol algorisme de xifrat en entorns de baix ample de banda degrada la veu a causa de l'augment de la pèrdua de paquets i latència dels paquets de qualitat, però quan l'ample de banda augmenta les trucades de VoIP xifrades proporcionen un millor servei en comparació amb un entorn sense seguretat.Las herramientas modernas de comunicación multimedia deben tener alta seguridad, alta disponibilidad y alta calidad de servicio (QoS). Ningún tipo de implementación de seguridad tendrá un impacto directo en la calidad de servicio. En este artículo se investiga como la seguridad de extremo a extremo impacta en la calidad de servicio de voz sobre el Protocolo de Internet (VoIP). La calidad de servicio se mide en términos de pérdida de proporción de paquetes, latencia y jitter utilizando diferentes algoritmos de encriptación, sin seguridad y sólo con el uso de cortafuegos IP en local y en redes de área amplia (LAN y WAN). Los resultados de las pruebas de laboratorio indican que el impacto general sobre el rendimiento de VoIP depende de la disponibilidad de ancho de banda y el algoritmo de cifrado que se utiliza. La implementación de cualquier algoritmo de cifrado en entornos de bajo ancho de banda degrada la voz debido al aumento de la pérdida de paquetes y latencia de los paquetes de calidad, pero cuando el ancho de banda aumenta las llamadas de VoIP cifradas proporcionan un mejor servicio en comparación con un entorno sin seguridad

    The Critical Success Factors for Implementation of CRM and Knowledge Management in a Work Setting

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    Customer Relationship Management is the most vigorous tools in our era and is the integration of trust, business and technology to gratify the requirements of the clients. CRM is a strategy of dealing with people, technology and process and need to be implemented precisely. CRM is the most outstanding business strategy that consolidates internal procedures and externals to generate and convey value to the spotted customers and CRM can easily neutralize competitive perils, provide a good source of roadmap for the company and customers. Moreover it may clarify the potential pitfalls in creating success for the company.CRM involves validating and evaluating critical success factors, which cover the three perspectives of CRM as the theoretical base, and which constitute a guide for companies in the implementation of the applications. Due to this, the desired benefits have intensified customer satisfaction and maintenance, by generating personalized products and value-added services. In this paper, the author investigates the factors that can positively leverage the implementation and use of CRM and creates differentiation among these factors and knowledge management factors. What is more, the paper aims at determining technical feature between CRM and knowledge management and managed to compare KM with CRM successfully

    ZigBee/ZigBee PRO security assessment based on compromised cryptographic keys

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    Sensor networks have many applications in monitoring and controlling of environmental properties such as sound, acceleration, vibration and temperature. Due to limited resources in computation capability, memory and energy, they are vulnerable to many kinds of attacks. The ZigBee specification based on the 802.15.4 standard, defines a set of layers specifically suited to sensor networks. These layers support secure messaging using symmetric cryptographic. This paper presents two different ways for grabbing the cryptographic key in ZigBee: remote attack and physical attack. It also surveys and categorizes some additional attacks which can be performed on ZigBee networks: eavesdropping, spoofing, replay and DoS attacks at different layers. From this analysis, it is shown that some vulnerabilities still in the existing security schema in ZigBee technology.Les xarxes de sensors tenen moltes aplicacions en el control i la monitorització de les propietats del medi ambient, com ara el so, l¿acceleració, la vibració i la temperatura. A causa dels limitats recursos en la capacitat de càlcul, la memòria i l'energia són vulnerables a molts tipus d'atacs. L'especificació ZigBee basada en l'estàndard 802.15.4, defineix un conjunt de capes, adaptada específicament per a xarxes de sensors. Aquestes capes suporten missatgeria segura mitjançant criptografia simètrica. Aquest article presenta dues formes diferents per agafar la clau de xifrat en ZigBee: atac a distància i atacs físics. També les enquesta i classifica alguns atacs addicionals que es poden realitzar en les xarxes ZigBee: espionatge, falsificació, reproducció i atacs DoS en les diferents capes. A partir d'aquesta anàlisi, es demostren algunes vulnerabilitats existents en l'esquema de seguretat en tecnologia ZigBee.Las redes de sensores tienen muchas aplicaciones en el control y la monitorización de las propiedades del medio ambiente, como el sonido, la aceleración, la vibración y la temperatura. Debido a los limitados recursos en la capacidad de cálculo, la memoria y la energía son vulnerables a muchos tipos de ataques. La especificación ZigBee basada en el estándar 802.15.4, define un conjunto de capas, adaptada específicamente para redes de sensores. Estas capas soportan mensajería segura mediante criptografía simétrica. Este artículo presenta dos formas diferentes para coger la clave de cifrado en ZigBee: ataque a distancia y ataques físicos. También las encuesta y clasifica algunos ataques adicionales que se pueden realizar en las redes ZigBee: espionaje, falsificación, reproducción y ataques DoS en las diferentes capas. A partir de este análisis, se demuestran algunas vulnerabilidades existentes en el esquema de seguridad en tecnología ZigBee

    Thiamine can decrease Lactate and Creatinine level after Coronary Artery Bypass Surgery in Patients with Mild Systolic Dysfunction

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    Introduction: During cardiopulmonary bypass, oxidative stress happens in the patient's cells due to blood contact with various levels of synthetic materials. It can activate inflammatory process and release factors such as IL-6, CRP, and Neutrophils witch may hurt different organs. In recent years, many efforts have been made to prevent this type of damage, however, no single treatment has been proposed to reduce this risk. Antioxidant substances such as Thiamine is important in cell defense against free oxygen radicals. Regarding this issue, in this study, the effect of thiamine on lactate levels in patients undergoing coronary artery bypass graft surgery has been investigated.Materials and methods: In this study, 140 patients from 25 to 65 years old with mild systolic dysfunction (EF = 45-55%) who were candidates for elective CABG surgery in two groups: control and purpose (patients receiving Thiamine) were examined. All of these patients were anesthetized in an identical manner, and were subjected to a heart-lung pump. Serum lactate levels were measured before, during and 6, 12, 18, and 24 hours after surgery. All data collected in a questionnaire were recorded and evaluated using spss statistical software.Results: Study groups showed no significant differences regarding demographics and underlying diseases. Serum lactate was significantly lower in thiamine group during the first 24 hours after surgery (except before operation and 2 hours later) (p <0.05).Creatinine level in two groups before surgery was not significantly different ,However, it was significantly lower in case group 24 hours after surgery(1.54±0.14 vs. 1.24±0.19; p: 0.001).Also, dose of Inotropes in  patients who received thiamine, was significantly lower than the control group (p= 0.001). Extubation was longer in control group (15.4±4.9 vs. 13.15±4.1; p=0.003) while ICU stay was not different.Conclusion: It seems that thiamine administration before cardiopulmonary bypass, in patient with decreased left ventricular function, can decrease serum lactate as tissue perfusion marker and also improve kidney function

    The relationship between s100β and cerebral oximetry trend in patients undergoing CABG with cardiopulmonary bypass

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    Background: CABG is among the most common cardiac procedures often done as on pump surgery. There are however, there is always the risk for potential neurologic and neurocognitive insults in CABG. S100β is a biomarker for CNS damage. Cerebral oximetry using NIRS has been developed for CNS monitoring especially cardiac surgery. This study was designed to find the relationship between serum levels of s100β and cerebral oximetry in CABG patients.Methods: in an observational study, 44 adult 40-75 years patients entered the study for elective CABG. Serum levels of s100β were assessed at two times during CPB; i.e. just after aortic clamping and immediately after aortic declamping; while the results were compared with right and left cerebral oximetry readings (NIRS); however, NIRS was measured at baseline, during start of cardiopulmonary bypass (CPB), during aortic clamping, and finally at off-clamping the aorta. Repeated Measures ANCOVA (analysis of covariance), multiple linear regression models and Spearman correlation coefficient with scatter plot were used for data analysis. P value less than 0.05 considered significant.Results: no linear correlation between s100β and NIRS was found according to correlation coefficients. Only among the patients whose s100β was more than 10, the scatter plots demonstrated a positive linear relationship between s100β and right NIRS (spearman correlation coefficient= 0.792; P value=0.006).Conclusions: the study failed to demonstrate a relationship between on-CPB NIRS numbers and serum s100β in adult patients undergoing CABG during the bypass interval; further studies are suggested to evaluate potential predictive value of NIRS in brain ischemia

    Comparison of Different Ventilation Strategies during Cardiopulmonary Bypass in Smoker Patients Under Cardiac Surgery

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    Background: Control of pulmonary ventilation during surgery, especially heart surgery, is very important. Therefore, in this study, we will compare different ventilation strategies during cardiopulmonary bypass in smokers undergoing cardiac surgery. Methods: A total of 42 patients who had a clinical indication for CABG were included in this study. Patients were randomly divided into two groups.  All patients were operated on by the same surgeon and cardiac anesthesia team in the same condition. The patient data includes age, sex, height, weight, and spirometry indices (FEV1, FVC, FEV1 / FVC, MMEF, PEF, PaO2, PaCO2, PaO2 / fio2, PaO2 / fio2, and Pent. T)  were recorded prospectively for each patient. Results: Examines the spirometry indices of patients in the two groups in both pre-procedure and off-pump time, do not show significant changes (P<0.005). Conclusion: The use of different ventilation strategies in smokers undergoing CABG surgery could not cause significant changes in patients' respiratory parameters

    Bio-signal based control in assistive robots: a survey

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    Recently, bio-signal based control has been gradually deployed in biomedical devices and assistive robots for improving the quality of life of disabled and elderly people, among which electromyography (EMG) and electroencephalography (EEG) bio-signals are being used widely. This paper reviews the deployment of these bio-signals in the state of art of control systems. The main aim of this paper is to describe the techniques used for (i) collecting EMG and EEG signals and diving these signals into segments (data acquisition and data segmentation stage), (ii) dividing the important data and removing redundant data from the EMG and EEG segments (feature extraction stage), and (iii) identifying categories from the relevant data obtained in the previous stage (classification stage). Furthermore, this paper presents a summary of applications controlled through these two bio-signals and some research challenges in the creation of these control systems. Finally, a brief conclusion is summarized

    Wrist-Worn Wearables Based on Force Myography: On the Significance of User Anthropometry

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    Background Force myography (FMG) is a non-invasive technology used to track functional movements and hand gestures by sensing volumetric changes in the limbs caused by muscle contraction. Force transmission through tissue implies that differences in tissue mechanics and/or architecture might impact FMG signal acquisition and the accuracy of gesture classifier models. The aim of this study is to identify if and how user anthropometry affects the quality of FMG signal acquisition and the performance of machine learning models trained to classify different hand and wrist gestures based on that data. Methods Wrist and forearm anthropometric measures were collected from a total of 21 volunteers aged between 22 and 82 years old. Participants performed a set of tasks while wearing a custom-designed FMG band. Primary outcome measure was the Spearman’s correlation coefficient (R) between the anthropometric measures and FMG signal quality/ML model performance. Results Results demonstrated moderate (0.3&thinsp;≤|R|&thinsp;&lt;&thinsp;0.67) and strong (0.67&thinsp;≤&thinsp;|R|) relationships for ratio of skinfold thickness to forearm circumference, grip strength and ratio of wrist to forearm circumference. These anthropometric features contributed to 23–30% of the variability in FMG signal acquisition and as much as 50% of the variability in classification accuracy for single gestures. Conclusions Increased grip strength, larger forearm girth, and smaller skinfold-to-forearm circumference ratio improve signal quality and gesture classification accuracy
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