Abstract

Improperly designed brick masonry walls cause undesirable effects under seismic loading in both brick masonry in-filled reinforced concrete (RC) frames and masonry load bearing wall structures. Doors and windows (openings) are unavoidable components in brick masonry in-filled RC structures and masonry load bearing wall structures because of its functional and ventilation requirements. The presence of openings in brick masonry walls reduces the lateral stiffness and strength of the wall in both RC and load bearing structures, which changes the actual behavior of structure. If these openings are located in the restricted zones like areas within middle two thirds of a wall wall, then the wall needs to be strengthened by providing necessary horizontal/vertical (bands) structural elements such as lintel or lintel bands around them. Lack of such structural elements may cause the structure to undergo severe damage during the earthquake event. In this paper, two case studies,(a) the presence of openings in infill wall with or without lintel and lintel band (b) the presence of openings in load bearing wall with or without lintel and lintel band is studied, to know the nonlinear response of brick masonry in-filled RC frame and load bearing wall under seismic loading. To understand the behaviour of the infilled frames and load bearing wall, a two dimensional (2D) infilled frame and load bearing wall is modeled and analyzed using a tool based on Applied Element Method (AEM). Nonlinear static pushover (SPO) is performed to estimate capacity of the models.

Abstract

Nuclear power plant is one of the largest source of producing electricity in India after thermal, hydroelectric and renewable sources of electricity. As of 2013, India has 21 nuclear reactors in operation in 6 nuclear power plants, having an installed capacity of 5780 MW and producing a total of 30, 293 GWh of electricity while six other reactors are under construction and are expected to generate an additional 6,100 MW. After 2011 Fukushima earthquake in Japan, safety of nuclear reactors has become a major concern. For assessing safety it is utmost important to have information on expected earthquake events. In case of lack of sufficient information, artificial ground motions may be generated by using geological features and faults information. This study presents simulation of near field generated ground motions of Rawatbhata nuclear power plant. For this purpose, three faults nearer to the power plant have been selected to the generate ground motions using semi-empirical approach. It is observed that as the source (M) of the earthquake increases, the amplitude of the ground motion, duration and energy content increases. Similarly, the spectral accelerations also increase due to all three active faults.

Abstract

The process of crustal deformation depends on the type of tectonic plate interactions viz. convergent, divergent and transform. For all the three cases, the topography effect is different. However, higher elevations and huge compressions are measured at convergent plate margins. Past observations reveal that these margins are very much prone to great earthquakes especially at the locations where oceanic plate is subducting underneath a continental plate. For the purpose of understanding horizontal and vertical displacement profiles on both the plates, a study considering the interaction between oceanic and continental plate which are resting on lithosphere mantle is carried out. Two dimensional finite element models were developed and analyzed using commercially available software ABAQUS. Contact properties are defined between plates so that effect of friction is calculated. All plates have an elastic rheology and slip is allowed at the interfaces. The models demonstrate that inclination angles leading to subduction or collision affects the length of vertical and horizontal displacements. Also, increasing the coefficient of friction decreases the vertical deformation but increases the amount of subsidence. This study concludes that the inclination angle and coefficient of friction plays a vital role for the development of varied crustal deformations at convergent plate margins.

Abstract

Earthquake performance of Reinforced concrete bare frame has been well documented in the past. Also, damage patterns in reinforced concrete frames during the past earthquakes have been extensively studied. However, more recently, several destructive earthquakes, including the 1999 Athens (Greece) earthquake, the 1999 Ýzmit and Düzce earthquakes (Turkey), 1999 Chi Chi (Taiwan) earthquake, 2001 Bhuj (India) earthquake, and the 2003 Boumerdes (Algeria) earthquake, have given more insights to performance of RC frame constructions. In order to understand the complete behavior of RC frame, it is required to study the performance from no loading condition till the complete collapse. In this paper, a set of four bare frames designed as per Indian Standards are considered. All the frames are subjected to Northridge earthquake ground motion. Newly developed numerical model called Applied Element Method (AEM) is considered for analysis. Initially, the linear analysis is carried out and the results were compared with commercially available software. Later, progressive collapse analysis is performed. Collapse process of each bare frame is discussed in detail.

Abstract

Different shapes of column cross sections are possible for design of structures which ultimately affect the overall performance. Various cross section reinforced concrete columns like square, circular, plus, L, and T shaped with same cross sectional area and reinforcement are modelled. In order to make this study more practically applicable, three models each of multi storeyed structures of different number of storeys were analysed for non-linear static responses. One of the models used conventional rectangular columns, second used circular columns throughout and another model employed combination of various geometrically possible column cross sections such as L, T and plus (+) shaped columns. The study compares response modification factors for above mentioned structures.

Abstract

Past earthquakes in India have caused maior damage to structures even for lesser peak ground acceleration than it is designed for. This is because of lack of incorporation of earthquake resistant design features in the structure. In India most of the structures are designed for gravity loads only. It is due to lack of knowledge and awareness of earthquake resistant design and the myth that earthquake resistant design is costlier. in this view, present study aims at comparing normal detailing as per IS 456: 2000 and ductile detailing as per IS 13920 (Proposed draft) in terms of its capacity, damage and cost. A parametric study has been carried out by considering a 5 storey building, designed for gravity loads as well as, lateral load as per IS 18931002, for different seismic zones (Zone II to V) and results are compared. Static Non Linear (Pushover) analysis and fragility analysis are performed for estimation of post damage …

Abstract

Several biometric-based remote user authentication schemes using smart cards have been proposed in the literature in order to improve the security weaknesses in user authentication system. In 2012, An proposed an enhanced biometric-based remote user authentication scheme using smart cards. It was claimed that the proposed scheme is secure against the user impersonation attack, the server masquerading attack, the password guessing attack, and the insider attack and provides mutual authentication between the user and the server. In this paper, we first analyze the security of An’s scheme and we show that this scheme has three serious security flaws in the design of the scheme: (i) flaw in user’s biometric verification during the login phase, (ii) flaw in user’s password verification during the login and authentication phases, and (iii) flaw in user’s password change locally at any time by the user. Due to these security flaws, An’s scheme cannot support mutual authentication between the user and the server. Further, we show that An’s scheme cannot prevent insider attack. In order to remedy the security weaknesses found in An’s scheme, we propose a new robust and secure anonymous biometric-based remote user authentication scheme using smart cards. Through the informal and formal security analysis, we show that our scheme is secure against all possible known attacks including the attacks found in An’s scheme. The simulation results of our scheme using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool ensure that our scheme is secure against passive and active attacks. In addition, our scheme is also comparable in terms of the communication and computational overheads with An’s scheme and other related existing schemes. As a result, our scheme is more appropriate for practical applications compared to other approaches.

Abstract

An integrated EPR (Electronic Patient Record) information system of all the patients provides the medical institutions and the academia with most of the patients’ information in details for them to make corrective decisions and clinical decisions in order to maintain and analyze patients’ health. In such system, the illegal access must be restricted and the information from theft during transmission over the insecure Internet must be prevented. Lee et al. proposed an efficient password-based remote user authentication scheme using smart card for the integrated EPR information system. Their scheme is very efficient due to usage of one-way hash function and bitwise exclusive-or (XOR) operations. However, in this paper, we show that though their scheme is very efficient, their scheme has three security weaknesses such as (1) it has design flaws in password change phase, (2) it fails to protect privileged insider attack and (3) it lacks the formal security verification. We also find that another recently proposed Wen’s scheme has the same security drawbacks as in Lee at al.’s scheme. In order to remedy these security weaknesses found in Lee et al.’s scheme and Wen’s scheme, we propose a secure and efficient password-based remote user authentication scheme using smart cards for the integrated EPR information system. We show that our scheme is also efficient as compared to Lee et al.’s scheme and Wen’s scheme as our scheme only uses one-way hash function and bitwise exclusive-or (XOR) operations. Through the security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks.

Abstract

The authentication protocols are trusted components in a communication system in order to protect sensitive information against a malicious adversary in the client-server environment by means of providing a variety of services including users' privacy and authentication. In the cryptographic protocols, understanding the security failures is the key for both patching to the existing protocols and designing the future protocols. Recently, in 2014, Wang proposed an improved Elliptic Curve Cryptography (ECC) based anonymous remote authentication scheme using smart card and claimed that the proposed scheme is secure against password guessing attack, smart card lost/stolen verifier attack, and also preserves user anonymity and prevents credential leakage. However, in this paper, we show that Wang's scheme fails to preserve the user anonymity and does not prevent the off-line password guessing attack, credential leakage and smart card lost/stolen verifier attack. In order to withstand those security pitfalls found in Wang's scheme, we aim to propose a new secure privacy-preserving ECC-based client authentication with key agreement protocol using smart card. Through the formal and informal security analysis we show that our scheme is secure against possible known attacks including the off-line password guessing attack, credential leakage attack and smart card lost/stolen verifier attack. Our scheme also preserves the user anonymity property. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks. Our scheme provides high security along with low computational and communication costs. As a result, our scheme is practically suitable for mobile devices in the client-server environment as compared to other related schemes in the literature.

Abstract

In real-life applications, ensuring secure transmission of data over public network channels to prevent malicious eavesdropping of the data is an important issue in distributed network environment. There are several potential security risks in protecting data and providing access control over the data. It is a challenging problem to manage dynamically the access rights to the resources and protect them from unauthorized access.Several migration access control mechanisms have been proposed in the literature using hierarchical structure to manage the cryptographic keys to prevent from unauthorized access of resources. However, most of them suffer from some known attacks and they do not efficiently support all required dynamic properties for mobile agent environment. Since, in practical scenarios, from time to time changing of decryption key of a confidential file provides maximum security for the system, it affects significantly the performance of the key management mechanism. In this paper, we propose a novel dynamic migration access control mechanism for the mobile agents (DMAMA) in a distributed network environment using symmetric-key cryptosystem. Further, we provide an elliptic curve cryptography based signature (El-Gamal type) on the decryption key assigned to the confidential file to avoid unauthorized modifications by an attacker. Moreover, DMAMA provides an efficient solution to the dynamic property such as changing decryption key of a confidential file, whereas other schemes do not provide. In addition, DMAMA is efficient in computation and storage overheads as compared to the other related existing schemes. Through the informal and formal security analysis, we show that DMAMA is secure against possible known attacks including man-in-the-middle attack as well as DMAMA provides backward secrecy to the decryption key of a confidential file when adding a new node or creating a new relationship in the existing hierarchy. As a result, higher security, low computational and storage overheads along with efficient access control properties make DMAMA more suitable for practical applications compared to the other related schemes.