Baihaqi I.,Sepuluh Nopember Institute of Technology |
Sohal A.S.,Monash University
Production Planning and Control | Year: 2013
Information sharing has been cited as one of the major means to enhance supply chain performance. It allows companies to better coordinate their activities with their supply chain partners that lead to increased performance. This study conceptualises and assesses several factors that influence the degree of information sharing in supply chains, namely integrated information technologies, internal integration, information quality and costs-benefits sharing. The relationship between the degree of information sharing and organisational performance is then tested. Data from 150 manufacturing companies were collected and proposed relationships are examined using structural equation modelling. The results show that integrated information technologies and information quality have positive influence on the intensity of information sharing. However, internal integration and costs-benefits sharing do not relate to the intensity of information sharing. This study finds that information sharing does not directly relate to organisational performance. Its relationship is mediated by collaboration practices with supply chain partners. This suggests that information sharing is essential but insufficient by itself to bring significant performance improvements. © 2013 Copyright Taylor and Francis Group, LLC.
Plack C.J.,University of Manchester |
Arifianto D.,Sepuluh Nopember Institute of Technology
Journal of the Acoustical Society of America | Year: 2010
On- and off-frequency compression at the 4000- and 8000-Hz cochlear places were estimated using a new version of the additivity of forward masking (AFM) technique, that measures the effects of combining two non-overlapping forward maskers. Instead of measuring signal thresholds to estimate compression of the signal as in the original AFM technique, the decrease in masker threshold in the combined-masker condition compared to the individual-masker conditions is used to estimate compression of the masker at the signal place. By varying masker frequency it is possible to estimate off-frequency compression. The maskers were 500-Hz-wide bands of noise, and the signal was a brief pure tone. Compression at different levels was estimated using different overall signal levels, or different masker-signal intervals. It was shown that the new AFM technique and the original AFM technique produce consistent results. Considerable compression was observed for maskers well below the signal frequency, suggesting that the assumption of off-frequency linearity used in other techniques may not be valid. Reducing the duration of the first masker from 200 to 20 ms reduced the compression exponent in some cases, suggesting a possible influence of olivocochlear efferent activity. © 2010 Acoustical Society of America.
Shabri A.,University of Technology Malaysia |
Suhartono,Sepuluh Nopember Institute of Technology
Hydrological Sciences Journal | Year: 2012
This paper investigates the ability of a least-squares support vector machine (LSSVM) model to improve the accuracy of streamflow forecasting. Cross-validation and grid-search methods are used to automatically determine the LSSVM parameters in the forecasting process. To assess the effectiveness of this model, monthly streamflow records from two stations, Tg Tulang and Tg Rambutan of the Kinta River in Perak, Peninsular Malaysia, were used as case studies. The performance of the LSSVM model is compared with the conventional statistical autoregressive integrated moving average (ARIMA), the artificial neural network (ANN) and support vector machine (SVM) models using various statistical measures. The results of the comparison indicate that the LSSVM model is a useful tool and a promising new method for streamflow forecasting.Editor D. Koutsoyiannis; Associate editor L. SeeCitation Shabri, A. and Suhartono, 2012. Streamflow forecasting using least-squares support vector machines. Hydrological Sciences Journal, 57 (7), 1275-1293. © 2012 Copyright 2012 IAHS Press.
Cahyadi M.N.,Hokkaido University |
Cahyadi M.N.,Sepuluh Nopember Institute of Technology |
Heki K.,Hokkaido University
Journal of Geophysical Research: Space Physics | Year: 2013
We studied ionospheric disturbances associated with the two large earthquakes in Sumatra, Indonesia, namely, the 2007 Bengkulu and the 2005 Nias earthquakes, by measuring the total electron contents (TEC) using a regional network of global positioning system (GPS) receivers. We first focus on coseismic ionospheric disturbances (CIDs) of the Bengkulu earthquake (M w 8.5). They appeared 11-16 min after the earthquake and propagated northward as fast as ~0.7 km/s, consistent with the sound speed at the ionospheric F layer height. Resonant oscillation of TEC with a frequency of ~5 mHz continued for at least 30 min after the earthquake. The largest aftershock (Mw 7.9) also showed clear CIDs similar to the main shock. A CID propagating with the Rayleigh wave velocity was not observed, possibly because the station distribution did not favor the radiation pattern of the surface waves. This earthquake, which occurred during a period of quiet geomagnetic activity, also showed clear preseismic TEC anomalies similar to those before the 2011 Tohoku-Oki earthquake. The positive and negative anomalies started 30-60 min before the earthquake to the north and the south of the fault region, respectively. On the other hand, we did not find any long-term TEC anomalies within 4-5 days before the earthquake. Co- and preseismic ionospheric anomalies of the 2005 Nias earthquake (Mw 8.6) were, however, masked by strong plasma bubble signatures, and we could not even discuss the presence or absence of CIDs and preseismic TEC changes for this earthquake. Key Points Bengkulu 2007 and Nias 2005 earthquake ©2013. American Geophysical Union. All Rights Reserved.
Semin,Sepuluh Nopember Institute of Technology
International Review of Mechanical Engineering | Year: 2012
In this article, previous work on the application of injector on CNG engines is reviewed. In the review of injector, the spray characteristics, the gas jet structure, the effect of injector nozzle geometry on fuel-air mixing, injector nozzle coefficients of discharge, injector nozzle spray tip penetration and cone angle as well as injector nozzle orifice shapes are outlined. Fuel-air mixing increases as the orifice diameter decreases. This can be a significant advantage for small orifice nozzles. However, multiple orifices are required to meet the desired mass flow rate as orifice diameter decreases. © 2012 Praise Worthy Prize S.r.l. - All right reserved.
Iskandriawan B.,Sepuluh Nopember Institute of Technology
International Journal of Applied Engineering Research | Year: 2014
An investigation of the performance of split air conditioning (AC) unit in some apartments around Jabodetabek is reported. The type of split AC unit and interior design of the apartments is uniquely developed to examine their effect to the cooling coefficient of performance (COPc). The investigation was focused on the establishment of the flow pattern uniqueness depend of the air conditioning unit types. Using computational fluid dynamics tool, several variables were exploited such as type of split AC, apartment location, air temperature and velocity. It is obtained specific air flow pattern from each room within operated split AC unit which is determine the COPc rates.Based on the 25 simulation, cassette AC types succeed in almost 5 apartment unit only at Kemang View, Bekasi it is only at the second fail with the floor suspended type. They succeed to decrease the room temperature spread inside the apartment room unit. Airflow pattern of cassette is the best amongst them. The second position is the wall types; they win in Season City, Icon Condotel and Paragon Square only fail in East Casablanca and Kemang View. The lowest COPc is the floor standard types; they unsucceed in Season City, Icon Condotel and Paragon Square. Practical applications:The effort to reduce the electricity energy consumption of air conditioning operation in the building industry is in line to the Indonesia government policy. The selection of air conditioning unit which is the best COPc is the one method to achieve the energy saving program. Moreover the number of apartment construction in Indonesia is very excessive especially in the big cities such as in Jabodetabek (Jakarta, Bogor, Depok, Tangerang and Bekasi) area. © Research India Publications.
Darmawan M.S.,Sepuluh Nopember Institute of Technology
Magazine of Concrete Research | Year: 2010
Different types of corrosion may arise in steel reinforcement, such as general corrosion, pitting corrosion, hydrogen embrittlement, stress corrosion cracking and corrosion fatigue. However, corrosion of steel reinforcement in reinforced concrete (RC) structures can be classified into two categories: general (uniform) corrosion and pitting (localised) corrosion. In general, concrete researchers use uniform corrosion to study the effect of corrosion on RC structures. This approach is not accurate for concrete structures subjected to chloride attack, which usually experiences pitting corrosion. This paper describes an accelerated corrosion test used to obtain statistical parameters of maximum pit-depths distribution of corroded steel in a RC structure. Using probabilistic analysis, these statistical parameters are combined with statistical parameters of RC beams (i.e. beam dimensions, concrete strength, steel yield strength, cover thickness, workmanship quality, in situ strength factor, model error for flexure and shear and also corrosion rate) to determine the effect of corrosion on flexural and shear strength of RC beams. Using the proposed pitting corrosion model improves service life prediction of RC structures in a chloride environment. © 2010 Thomas Telford Ltd.
Budipriyanto A.,Sepuluh Nopember Institute of Technology
Procedia Engineering | Year: 2013
This paper addresses the application of blind source separation technique for identifying dynamic parameters of a seismic-excited multi-story building from its measured response. The structure was an instrumented moment-resisting frame office building. Its acceleration responses at different building floors were recorded during four earthquakes occurred in 2002. In this study second order blind identification - a class of blind source identification technique-was employed to obtain the structure's dynamic parameters, i.e., natural frequency and damping factor. The results of this study were substantiated through comparison with the results of investigations carried out for dynamic parameter identification of the same building using different techniques. Results of this study were encouraging. It indicated that the methodology employed in this study could be beneficially applied for identifying dynamic parameters of the building under seismic ground motions. © 2013 The Authors.
Handogo R.,Sepuluh Nopember Institute of Technology
Asia-Pacific Journal of Chemical Engineering | Year: 2012
The aim of this research is to get the optimum operating condition of crude distillation unit in order to get the highest profit for the crude oil refinery industry. Feeds specification data are taken from an Indonesian crude oil refinery. Simulation was done by using ASPEN PLUS (Aspen Technology, Inc, Burlington, MA, USA). The design variable for this research is the temperature of preflash column furnace. Optimization was done by considering the maximum profit. Based on the result in part one, where intermediate and light cold test molar flowrates and the quality of heavy naphtha in the 95% liquid volume ASTM D86 at 415K and light kerosene distillate in the 95% liquid volume ASTM D86 at 469K are held constant, the optimum condition is found at the furnace preflash temperature of 572K with a profit of US$ 9.62 per m3 crude oil. While in part two, where heavy naphtha and light kerosene distillate molar flowrates and the quality of intermediate in the 95% liquid volume ASTMD86 at 443K and light cold test in the 95% liquid volume ASTMD86 at 605K are held constant, the optimum condition is found at the furnace preflash temperature of 533K with a profit of US$ 7.74 per m 3 crude oil. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
News Article | January 27, 2016
Using lasers and a window in a ship's hull, researchers will assess how quickly the efficiency of the ship declines, and then how to balance fuel efficiency and the cost of putting a ship in dry dock to clean it. "Essentially we've built a laboratory worth thousands of dollars inside the hull of the ship. Once we clearly know how things are growing on the bottom, and the effect this has on fuel efficiency, we can suggest more informed anti-fouling strategies, saving time and money for boat operators and passengers," says Professor I Ketut Aria Pria Utama from Sepuluh Nopember Institute of Technology (ITS). The team combines the maritime experience of engineers from the Sepuluh Nopember Institute of Technology with fluid mechanics expertise at the University of Melbourne and the University of Southampton, along with protective coating group Hempel. As soon as a new ship enters the ocean it starts to accumulate fouling – bacteria settle within days, followed within weeks by plants and animals. It's a particular problem in the tropical waters of Indonesia and northern Australia. "The real costs for shipping operators are hard to determine," says Associate Professor Nicholas Hutchins of the University of Melbourne. "Research discussions with ship operators all go well until we say 'and now we just need to put a small hole in the side of your ship'. But our Indonesian collaborators persuaded the PT Dharma Lautan Utama line to allow us to install a 30cm window in the hull of one of their inter-island ferries, the 71 metre Dharma Kencana IX, which transports people between Java and South Sumatra." Normally a boat can do this route in two hours, but with a high amount of marine growth on the boat, the journey can easily take double the time. The US Navy estimated that for its Arleigh Burke-class destroyer, resistance due to fouling costs about $2.3 million per ship per year in extra fuel consumption. Modern container ships are 10 to 15 times heavier. So the waste of fuel could be much higher. For the fleet of ships operating in Australian and Indonesian waters the costs could be billions of dollars per annum. And there's a significant carbon footprint as well: a substantial proportion of the fuel burnt by a large ship is used to overcome drag, and even a moderate amount of biofouling adds substantially to this. "Fifteen thousand dollars of seed funding from the Australia Indonesia Centre has enabled us to reach out to industry and other collaborators to build this into a much bigger, $200,000 dollar project, including securing a collaborative grant with the University of Southampton in the UK," Nicholas says.