scholarly journals Traditional Ship Stability Evaluation in Toba Lake

2021 ◽  
Author(s):  
Abdy Kurniawan ◽  
Wilmar Jonris Siahaan

Toba Lake is a major tourist destination in Indonesia, and traditional boats are a popular mode of transportation for residents and tourists alike. However, these traditional ships have been involved in multiple accidents with significant casualties. This study aims to evaluate the stability of the ship according to the conditions of the local water area. The results showed that traditional boats that have been modified to have double decks (to allow for higher customer capacity) have poor stability, especially in bad weather conditions. To maintain sailing safety, it is recommended to recondition the ship into a single deck, avoiding overloads and bad weather. Keywords: Ship Stability, Toba Lake, Evaluation

2020 ◽  
Vol 20 (5) ◽  
pp. 273-280
Author(s):  
Seungwon Shin ◽  
Seongnoh Ahn ◽  
Sungsu Lee ◽  
Jongwon Jung

Approximately 76% of the reservoirs built in Korea are facilities that are more than 50 years old. The risk of disasters has increased because of reservoir aging and the deepening polarization of drought and floods caused by abnormal weather conditions. In addition, the number of earthquakes has been gradually increasing in Korea, and anxiety has increased significantly because of the recent series of large earthquakes since the earthquakes in Pohang and Gyeongju. Accordingly, risk assessment and preparation are required through the stability evaluation of earthquakes in old reservoirs. The stability evaluation method, based on the limit equilibrium method, depends highly on the soil strength parameters; hence, it is essential to identify the soil strength parameters accurately. However, even though the soil strength parameters are of the same layer, they have different values because of the heterogeneity of the ground. It is difficult to select the representative value of the soil strength parameters because of the time and economic constraints of the ground survey. Therefore, in this study, the probability of failure of an old reservoir owing to seismic events was calculated, and the stability was evaluated. The water level and the uncertainty of the strength constant of the reservoir were considered. The analysis showed that the probability of collapse has increased because of the increase in the water level and the coefficient of variation of the friction angle, and the stability of the reservoir, considering the seismic events, was found to not satisfy the minimum factor of safety for slope activities.


2020 ◽  
Vol 2020 (1) ◽  
pp. 78-81
Author(s):  
Simone Zini ◽  
Simone Bianco ◽  
Raimondo Schettini

Rain removal from pictures taken under bad weather conditions is a challenging task that aims to improve the overall quality and visibility of a scene. The enhanced images usually constitute the input for subsequent Computer Vision tasks such as detection and classification. In this paper, we present a Convolutional Neural Network, based on the Pix2Pix model, for rain streaks removal from images, with specific interest in evaluating the results of the processing operation with respect to the Optical Character Recognition (OCR) task. In particular, we present a way to generate a rainy version of the Street View Text Dataset (R-SVTD) for "text detection and recognition" evaluation in bad weather conditions. Experimental results on this dataset show that our model is able to outperform the state of the art in terms of two commonly used image quality metrics, and that it is capable to improve the performances of an OCR model to detect and recognise text in the wild.


Author(s):  
A.A. Dronic A.A. ◽  

The article presents an assessment of the stability of introduced cherry varieties to spring return frosts in 2020 in the conditions of the sharply continental climate of the Astrakhan region. As a result of unfavorable weather conditions, the total damage score of all varieties was 2-5 points. Almost all the studied varieties showed an insufficient level of resistance to recurrent frosts.


2021 ◽  
Vol 11 (5) ◽  
pp. 2106
Author(s):  
Abdelali El Aroudi ◽  
Mohamed Debbat ◽  
Mohammed Al-Numay ◽  
Abdelmajid Abouloiafa

Numerical simulations reveal that a single-stage differential boost AC module supplied from a PV module under an Maximum Power Point Tracking (MPPT) control at the input DC port and with current synchronization at the AC grid port might exhibit bifurcation phenomena under some weather conditions leading to subharmonic oscillation at the fast-switching scale. This paper will use discrete-time approach to characterize such behavior and to identify the onset of fast-scale instability. Slope compensation is used in the inner current loop to improve the stability of the system. The compensation slope values needed to guarantee stability for the full range of operating duty cycle and leading to an optimal deadbeat response are determined. The validity of the followed procedures is finally validated by a numerical simulations performed on a detailed circuit-level switched model of the AC module.


2021 ◽  
Vol 13 (15) ◽  
pp. 8170
Author(s):  
Veronica Sanda Chedea ◽  
Ana-Maria Drăgulinescu  ◽  
Liliana Lucia Tomoiagă  ◽  
Cristina Bălăceanu ◽  
Maria Lucia Iliescu 

Known for its dry and semi-dry white wine, the Târnave vineyard located in central Transylvania is challenged by the current climate change, which has resulted in an increase of the period of active vegetation by approximately 15–20 days, the average annual temperature by 1–1.5 °C and also the amount of useful temperatures (useful thermal balance for the grapevine). Furthermore, the frost periods have been reduced. Transylvania is an important Romanian region for grapevine cultivation. In this context, one can use the climatic changes to expand their wine assortment by cultivating an autochthonous grapevine variety called Amurg. Amurg is a red grape cultivar homologated at SCDVV Blaj, which also homologated 7 cultivars and 11 clones. Because viticulture depends on the stability of meteorological and hydrological parameters of the growing area, its foundations are challenged by climate change. Grapevine production is a long time investment, taking at least five years before the freshly planted vines produce the desired quality berries. We propose the implementation of a climate change-based precision viticulture turn-key solution for environmental monitoring in the Târnave vineyard. This solution aims to evaluate the grapevine’s micro-climate to extend the sustainable cultivation of the Amurg red grapes cultivar in Transylvania with the final goal of obtaining Protected Designation of Origin (PDO) rosé and red wines from this region. Worldwide, the changing conditions from the existing climate (a 30-year average), used in the past hundred years to dictate local standards, such as new and erratic trends of temperature and humidity regimes, late spring freezes, early fall frosts, storms, heatwaves, droughts, area wildfires, and insect infestations, would create dynamic problems for all farmers to thrive. These conditions will make it challenging to predict shifts in each of the components of seasonal weather conditions. Our proposed system also aims to give a solution that can be adapted to other vineyards as well.


2000 ◽  
Vol 78 (10) ◽  
pp. 1831-1839 ◽  
Author(s):  
P Sound ◽  
M Veith

Daily activity patterns of male western green lizards, Lacerta bilineata (Daudin, 1802), at the edge of their northern distribution range in western Germany after the breeding season from June to October were recorded using implanted radio transmitters. Different activity indices discriminating between stimulation, duration, and length of movement were correlated with actual weather conditions (d0) and with weather conditions on the 2 previous days (d-1 and d-2). The lizards' dependence on weather showed two different phases throughout the study period. During the first period and in the period preceding a drastic change of weather in midsummer, weather had no significant influence on movement parameters. After that event, temperatures dropped and a strong dependence on weather of all movement parameters except those indicating displacements became apparent. Thresholds for 50% activity during this second phase were a maximum temperature of 17°C and a minimum humidity of 35%. Two days after periods of bad weather, the influence of weather conditions increased again. This can be explained by physiological deficits that require compensation during the period of marginal weather conditions prior to hibernation. Displacement movements were significantly longer than home-range movements and were neither triggered nor modulated by the weather. They must therefore represent activities such as patrolling territory boundaries.


2017 ◽  
Vol 11 (10) ◽  
pp. 2521-2533 ◽  
Author(s):  
Babak Yousefi-khangah ◽  
Saeid Ghassemzadeh ◽  
Seyed Hossein Hosseini ◽  
Behnam Mohammadi-Ivatloo

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Ming Wei ◽  
Yonghong Wang ◽  
Huafen Song

Sensitivity and numerical stability of an algorithm are two of the most important criteria to evaluate its performance. For all published turbine flow models, except Wang method, can be named the “top-down” method (TDM) in which the performance of turbines is calculated from the first stage to the last stage row by row; only Wang method originally proposed by Yonghong Wang can be named the “bottom-up” method (BUM) in which the performance of turbines is calculated from the last stage to the first stage row by row. To find the reason why the stability of the two methods is of great difference, the Wang flow model is researched. The model readily applies to TDM and BUM. How the stability of the two algorithms affected by input error and rounding error is analyzed, the error propagation and distribution in the two methods are obtained. In order to explain the problem more intuitively, the stability of the two methods is described by geometrical ideas. To compare with the known data, the performance of a particular type of turbine is calculated through a series of procedures based on the two algorithms. The results are as follows. The more the calculating point approaches the critical point, the poorer the stability of TDM is. The poor stability can even cause failure in the calculation of TDM. However, BUM has not only good stability but also high accuracy. The result provides an accurate and reliable method (BUM) for estimating the performance of turbines, and it can apply to all one-dimensional performance calculation method for turbine.


Author(s):  
Liliana V. Pinheiro ◽  
Conceição J. E. M. Fortes ◽  
João A. Santos

The risks associated with mooring of ships are a major concern for port and maritime authorities. Sea waves and extreme weather conditions can lead to excessive movements of vessels and mooring loads affecting the safety of ships, cargo, passengers, crew or port infrastructures. Normally, port activities such as ships’ approach manoeuvres and loading/unloading operations, are conditioned or suspended based solely on weather or wave forecasts, causing large economic losses. Nevertheless, it has been shown that some of the most hazardous events with moored ships happen on days with mild sea and wind conditions, being the culprit long waves and resonance phenomena. Bad weather conditions can be managed with an appropriate or reinforced mooring arrangement. A correct risk assessment must be based on the movements of the ship and on the mooring loads, taking into account all the moored ship’s system. In this paper, the development of a forecast and warning system based on the assessment of risks associated with moored ships in port areas, SWAMS ALERT, is detailed. This modular system can be scaled and adapted to any port, providing decision-makers with accurate and complete information on the behaviour of moored ships, movements and mooring loads, allowing a better planning and integrated management of port areas.


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