Design and Development of Power Management System of Unmanned Underwater Platform for Defence Application

Development of underwater weapon systems for defence application are carried out on unmanned underwater platform. Extensive testing and measurement of physical parameters are carried out during development phase trials. After several trials, system is qualified and installed on the actual platform. Mostly battery bank is used to power the unmanned platform. Design and development of power management system is an important issue of underwater platform to increase the underwater time of the platform. During development trials some additional equipments are also included for which power requirement was not considered during design of battery bank. This also becomes an issue to manage the power requirement of additional equipment beyond the design capability of the battery bank. Unmanned submersible platforms at a depth of 50 m to 70 m are used during development of underwater missile. Platform houses the missile to be tested, equipment required for missile launch and control of the platform. A power management system (PMS) with redundancy and fault tolerant features achieving reliability figure of 99 per cent has been designed, developed and tested successfully for underwater phase of missile launch. The system allows remote operation of individual or group of equipment, current monitoring, and isolation of faulty equipment. Power requirement for additional equipment on platform is also included in PMS without affecting the reliability of the system. Power control of equipment on requirement basis to save battery power, to increase underwater time of platform and to manage additional power requirement beyond the designed capacity of the battery bank is described in detail

Emerging Trends in Instrumentation in Rocket Motor Testing

Rocket motors are designed, developed, and evaluated for performance, and after repeated tests, are qualified for use in a spacecraft or missile system. Comprehensive instrumentation measurement plan is made to record physical parameters during evaluation and testing. In the last thirty years, a revolution has happened in the field of electronics that has benefited instrumentation in terms of accuracy, bandwidth, capacity, reliability and analysis. This paper describes the improvements in instrumentation that have happened in the field of rocket motor testing over a period of last three decades.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.63-69, DOI:http://dx.doi.org/10.14429/dsj.65.794

Design and Development of Redeployable Underwater Data Communication Link for Defence Application

Testing of underwater system for defence application is carried out from submersible platform at specified depth. The underwater platform houses the article under test, equipment and instruments required to conduct the test and to control the platform. During development phase of defence systems, large numbers of sensors are mounted on the test article and data is collected to validate the design. Data acquisition system, video camera and high speed video cameras are positioned on the platform to record physical parameters and observe visually the performance of the article under evaluation. Since the data and video signals are parallely recorded on ship, the bandwidth demand for real-time data communication from underwater platform to control station is very high. The existing technology presently used for underwater communication has limitation of bandwidth and not suitable for defence application. This paper describes in detail the design and development of a re-deployable data communication link by laying a specially designed negatively buoyant fibre optic cable in high-sea from ship to underwater platform to provide higher bandwidth required for defence application. The link has been successfully used for sea state less than one during evaluation of underwater defence system. The availability of bandwidth from underwater platform to control system can be increased significantly by laying fibre optic cable in high sea. It also provides unlimited bandwidth for the above requirement.

Hankel Rhotrices and Constructions of Maximum Distance Separable Rhotrices over Finite Fields

Many block ciphers in cryptography use Maximum Distance Separable (MDS) matrices to strengthen the diffusion layer. Rhotrices are represented by coupled matrices. Therefore, use of rhotrices in the cryptographic ciphers doubled the security of the cryptosystem. We define Hankel rhotrix and further construct the maximum distance separable rhotrices over finite fields

A Study on Prevalance of Hypothyroidism in Patients with Extra Hepatic Biliary Lithiasis

AIM : To show the prevalence of clinical or subclinical hypothyroidism in patients with gallstones and common bile duct stones Back ground : Studies have shown an increased prevalence of previously diagnosed hypothyroidism in gallstone patient and a delayed emptying of the biliary tract in hypothyroidism, explained partly by the missing pro relaxing effect of thyroxine on the sphincter of oddi contractility. Other explanations include the known link between thyroid failure and disturbances of lipid metabolism that may consecutively lead to change of the composition of the bile and motility of biliary tract. PATIENT AND METHOD : An observational study was done in Institute of Surgery, Rajiv Gandhi Government General Hospital, Chennai between June 2014 to June 2015. For the 195 patients with diagnosed gallstone / CBD stone, full history and clinical examination was taken and laboratory blood test for T3, T4 and TSH was done. A control group of 100 patients of similar age and sex profile admitted in same time period for other illness were also evaluated for hypothyroidism. RESULTS : Out of 195 patients with gallstone 148 (76%) were females and 47 (24%) males. Thyroid disorder in form of hypothyroidism was found in 45 (23%), from this percentage 36 (24%) were females and from this 27 (18%) were subclinical and 9 (6%) were clinical hypothyroidism and males were 9 (19%) with all subclinical cases except one. This was compared with a control group of 100 patients, 80 (80%) were females and 20 (20%) males. Hypothyroidism was found in 9 (9%) patients, all female. CONCLUSION AND RECOMMENDATION : There is a significant association between hypothyroidism and gallstones / CBD stones in both genders. Gallstone and CBD stone patients, especially females should be checked for serum TSH, T3 and T4 because of high incidence of hypothyroidism among this group

Method for fabricating zig-zag slabs for solid state lasers

A method for batch manufacturing of slabs for zig-zag lasers including steps of bonding two non-active media to either side of an active medium to form a sandwich, dicing the sandwich to provide slices, rendering two surfaces of each slice into total-internal-reflection (TIR) surfaces, and then dicing the slices perpendicular to the TIR surfaces to provide a plurality of zig-zag slabs

An Effective Deep Learning Based Multi-Class Classification of DoS and DDoS Attack Detection

In the past few years, cybersecurity is becoming very important due to the rise in internet users. The internet attacks such as Denial of service (DoS) and Distributed Denial of Service (DDoS) attacks severely harm a website or server and make them unavailable to other users. Network Monitoring and control systems have found it challenging to identify the many classes of DoS and DDoS attacks since each operates uniquely. Hence a powerful technique is required for attack detection. Traditional machine learning techniques are inefficient in handling extensive network data and cannot extract high-level features for attack detection. Therefore, an effective deep learning-based intrusion detection system is developed in this paper for DoS and DDoS attack classification. This model includes various phases and starts with the Deep Convolutional Generative Adversarial Networks (DCGAN) based technique to address the class imbalance issue in the dataset. Then a deep learning algorithm based on ResNet-50 extracts the critical features for each class in the dataset. After that, an optimized AlexNet-based classifier is implemented for detecting the attacks separately, and the essential parameters of the classifier are optimized using the Atom search optimization algorithm. The proposed approach was evaluated on benchmark datasets, CCIDS2019 and UNSW-NB15, using key classification metrics and achieved 99.37% accuracy for the UNSW-NB15 dataset and 99.33% for the CICIDS2019 dataset. The investigational results demonstrate that the suggested approach performs superior to other competitive techniques in identifying DoS and DDoS attacks