Journal Articles
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Item Use of swath data in realtime navigation by pattern recognition(Marine Geodesy, 1989) Prabaharan, N.; Sivakholundu, K. M.A new method is proposed with the aim of reducing dead reckoning error (DRE) during multibeam echosounding survey in deep ocean. Bathymetric data is used in this method to estimate DRE in position fixing. This method can be activated at any desired interval to check the DRE accumulation in addition to available external navigation systems. A pattern recognition algorithm is developed to quantify the shift in position of a selected bathymetric feature that has been observed already once. This difference is used to correct the position fixing and navigation dataItem Estuarine channel stability assessment through tidal asymmetry parameters(Journal of Coastal Research, 2009-03) Sivakholundu, K. M.; Mani J. S.; Idichandy V. G.; Kathiroli S.In an estuarine channel the tidal asymmetry, sediment transport, and morphology are interconnected. To maintain a stable channel, we need to take tidal asymmetry into account. A relationship connecting tidal asymmetry and sediment transport rate has been used to evaluate the relative merits of channel modification through numerical simulations. Two criteria have been identified for ensuring the channel stability: (a) maintaining ebb dominance and (b) minimizing the spatial gradient in the net sediment transport function ⟨q⟩. Using these criteria for a test case, we have evaluated Hooghly estuary (east coast, India), where heavy sedimentation is experienced and a permanent solution is needed. The approach provides better insight into the sedimentation pattern in a semidiurnal tidal process in a shallow estuary with braided channels. Among the factors affecting tidal asymmetry, the relative phase difference (β) between M2 and M4 current constituents has a major influence and is thus responsible for the sedimentation pattern. Through numerical study it was found that a combination of deepened, uniform channel with enhanced ebb flow led to a favorable β, indicating less deposition.Item A program to compute the area of an irregular polygon on a spheroidal surface(Computers and Geosciences, 1998) Sivakholundu, K. M.; Prabaharan, N.Item A new archaeological find in the Gulf of Cambay, Gujarat(Journal of the Geological Society of India, 2002) Kathiroli, S.; Badrinarayanan, S.; Venkata Rao, D.; Rajaguru, S.; Sivakholundu, K. M.; Sasisekaran, B.Detailed underwater surveys carried out in the Gulf of Cambay, about 20 km west of Hazira, deploying side scan sonar and sub bottom profiler brought to light, the presence of a submerged palaeochannel traceable to a length of 9 km. Associated with this on either side are basement like features found in a grid pattern at water depths of 20-40 m. Sub-surface sampling carried out with dredge and grab sampler revealed stone artefacts, potsherds, hearth pieces, animal bones and human teeth embedded in fluvial sands and silts. In the upper part of the deposit, a carbonised wooden log was found and dated to around 9500 years BP by 14C method. Marine magnetic survey carried-out does not indicate the presence of any major metallic debrislobjects. This appears to be one of the early records of prehistoric human activity of early Holocene age in the marine environment of India.Item Quantification of changes in seabed topography with special reference to Hansthal Creek, Gulf of Kachchh, India.(Journal of costal research, 1993-01) Pattanshetti, S.S.; Chauhan, Onkar.; Sivakholundu, K. M.Variations in the bathymetry in macrotidal Hansthal Creek between 1984 and 1950 along 14 closely spaced lines, are used to quantify the volumetric changes in seabed topography in terms of erosion/accretion. Two surfaces from the bathymetric data of 1984 and 1950 have been modelled. The profile wise comparison along the transects indicates a dynamic deformation due to distinct alteration in the shoreline and a shift in the channel course. The shoreline has retreated 650 and 450 m on the northern and southern banks respectively. The studies suggest scouring of horizontally deposited fine sediments (clays deposited in an antecedent depositional phase) in the Hansthal Creek due to existing dynamic equilibrium among (a) influence of physiography in amplifying the tidal range, (b) increased efflux due to contribution through inter-creek water movements, and (c) high magnitude currents. Magnitude of erosion in the creeks, particularly on the flanks, is much more than in the axial channel. The degree of the erosion reduces from the Hansthal Creek mouth to inland (area in the close vicinity of Little Gulf of Kachchh). During the last 34 years about 71.5 x 10 super(6) m super(3) from this creek during the course of the present study. Offshoreward movement of scoured sediments and their redeposition in the outer gulf as a fill in the paleo-channel is observed.Item Intra-annual studies of mixed layer depth in the Arabian Sea using a 3 ½ layer Indian ocean model(Bentham Open, 2009-09-04) Patnaik, K. V. K. R. K.; Sreenivas, P.; Venkata Ramu, Ch.; Arun Kumar, S. V. V.; Prasad, K. V. S. R.Mixed layer is the upper layer of the ocean, where significant physical, chemical and biological activities take place. Knowledge of mixed layer depth variability is important in the studies of air-sea interaction, acoustic propagation, heat transport and fisheries. The Arabian Sea experiences extremes in atmospheric forcing that lead to intra-annual and inter-annual variability. Since the climatic conditions over the Arabian Sea are highly variable, the mixed layer depth also changes seasonally. Hence the intra-annual variability of mixed layer depth in the Arabian Sea has been examined using 3 ½ layer Indian Ocean model. The model is integrated for 8 years (1993–2000) with annually varying monthly averaged winds derived from ERS-2 scatterometer. In addition to this data, inter annually varying monthly averaged satellite estimates of precipitation from Global Precipitation Climatology were also incorporated in the model. Model results show a steady deepening of mixed layer depth in the central Arabian Sea during southwest monsoon period. The model shows its capability to predict the shallow mixed layer depths caused by coastal upwelling off Somalia during southwest monsoon period and is able to capture the Lakshadweep high/low as it predicted successfully the deeper/shallow mixed layer observed during these periods.null.listelement.badge Significance of income generation activities under micro-finance: A study of micro-finance groups in wayanad district, kerala(Institute for Social and Economic Change, 2005) Mathew, Emil.The present paper discusses the necessity of promoting income-generating activities (IGAs) under micro-finance programmes. Under micro-finance programmes, the principle of joint liability ensures access to credit. In the absence of remunerative IGAs, peer pressure forces the members to borrow loans from various sources at the time of repayment and results in indebtedness. The present paper examines the factors influencing the members to undertake IGAs and puts forth some policies to promote productive activities.null.listelement.badge Does repayment indicate the success of micro-finance programme(Institute for Social and Economic Change, 2006) Mathew, Emil.This paper examines the patterns of loan utilisation and repayment among microfinance group members of Wayanad district of Kerala. It argues that 100 per cent repayment by members need not always indicate the success of group lending. As majority of the members have not undertaken income generating activities, the fear of social sanction and repeated interactions put pressure on them to depend on micro-finance loans at the time of repayment. The absence of alternative credit sources increases the financial dependence of the members over a period of their stay in micro-finance programme.null.listelement.badge Review article on the mental health of seafarers(0000) Chandra, Mihir.‘Sea the future’ is coined correctly by the name blue economy. But is the future beckons wellbeing of the ‘key worker’? While Covid 19 pandemic halted most of the economic juggernauts in lockdown; it could not put a spanner into the propellers of ships which kept trading for 90% of the global trade 24x7 around the COVID’s variants year, seafarers mental and physical health went through tough times. The articles reviewed had never seen through this unknown tunnel of this decade. Wisdom of hindsight is common but resilience to bounce back may be grasped out of foresight with learnings of gap analysis. Awareness of factors influencing health, as a building block for seafarers’ training from pre-sea level is to be envisioned in the mode of compulsory courseware. Physical fitness and mental toughness modules must be enshrined in courseware with pedagogy and soft skill development through case studies. Research work should pave the way for innovative tools to monitor seafarer health 24X7. The well-being of seafarers may then be addressed potentially.null.listelement.badge Enhancing cyber security awareness in maritime industry(0000) Chandra, Mihir.Cyber security is the combination of stakeholders, policies, processes and technologies to protect cyber assets of any industry. It is optimized to levels that help shipping personnel define, balance resources required with usability/manageability and the amount of risk offset. The aim of this paper is to develop understanding and awareness of key aspects of cyber security – identify threats, identify vulnerabilities, assess risk exposure, develop protection & detection measures & establish contingency plans. Furthermore, establish guidelines for operators on how to assess their ship’s operations & put in place necessary procedures and actions to maintain the security of cyber systems for marine industry. The integration of technology in shipping operations is being enabled by the integration of Information Technology and the Operation Technology on board ships. This has enhanced the threats of unauthorised access or malicious interventions to ship’s systems and networks. The measures to guard against cyber threats should include, (i) quantification and type of risks to security, environment and commerce if no cyber security measures are in place, (ii) due protection to IT and OT infrastructure and its networked equipment, (iii) management of access (iv) protecting data related with its sensitivity. With emerging technologies, there is a direct applicability of trends like Artificial Intelligence to enhance security and fraud prevention. Extending the use of Security Analytics for understanding and detecting risk level of vulnerabilities, improving the performance of own security policy by removal of unnecessary data, feature extraction and selection, data cut off, parallel processing, machine learning and deep learning algorithms – are some examples for the use of advanced technologies for improving Cybersecurity.