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Journal of Engineering and Technological Sciences
Published by Institut Teknologi Bandung
ISSN : 23375779     EISSN : 23385502     DOI : -
Core Subject : Engineering,
Engineering
Journal of Engineering and Technological Sciences welcomes full research articles in the area of Engineering Sciences from the following subject areas: Aerospace Engineering, Biotechnology, Chemical Engineering, Civil Engineering, Electrical Engineering, Engineering Physics, Environmental Engineering, Industrial Engineering, Information Engineering, Mechanical Engineering, Material Science and Engineering, Manufacturing Processes, Microelectronics, Mining Engineering, Petroleum Engineering, and other application of physical, biological, chemical and mathematical sciences in engineering. Authors are invited to submit articles that have not been published previously and are not under consideration elsewhere. Starting from Vol. 35, No. 1, 2003, full articles published are available online at http://journal.itb.ac.id, and indexed by Scopus, Index Copernicus, Google Scholar, DOAJ, GetCITED, NewJour, Open J-Gate, The Elektronische Zeitschriftenbibliothek EZB by University Library of Regensburg, EBSCO Open Science Directory, Ei Compendex, Chemical Abstract Service (CAS) and Zurich Open Repository and Archive Journal Database. Publication History Formerly known as: ITB Journal of Engineering Science (2007 – 2012) Proceedings ITB on Engineering Science (2003 - 2007) Proceedings ITB (1961 - 2002)
Arjuna Subject : -
Articles 1,267 Documents
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On Active Surge Control of Compression Systems via Characteristic Linearization and Model Nonlinearity Cancellation Simamora, Yohannes S.M.; Tjokronegoro, Harijono A.; Leksono, Edi
Journal of Engineering and Technological Sciences Vol 46, No 3 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1139.257 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.3.8

Abstract

A simple approach of active surge control of compression systems is presented. Specifically, nonlinear components of the pressure ratio and rotating speed states of the Moore-Greitzer model are transferred into the input vectors. Subsequently, the compressor characteristic is linearized into two modes, which describe the stable region and the unstable region respectively. As a result, the system’s state and input matrices both appear linear, to which linear realization and analysis are applicable. A linear quadratic regulator plus integrator is then chosen as closed-loop controller. By simulation it was shown that the modified model and characteristics can describe surge behavior, while the closed-loop controller can stabilize the system in the unstable operating region. The last-mentioned was achieved when massflow was 5.38 per cent less than the surge point.
Filtered-X Radial Basis Function Neural Networks for Active Noise Control Riyanto, Bambang; Anggono, Lazuardi; Uchida, Kenko
Journal of Engineering and Technological Sciences Vol 36, No 1 (2004)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (654.802 KB) | DOI: 10.5614/itbj.eng.sci.2004.36.1.2

Abstract

This paper presents active control of acoustic noise using radial basis function (RBF) networks and its digital signal processor (DSP) real-time implementation. The neural control system consists of two stages: first, identification (modeling) of secondary path of the active noise control using RBF networks and its learning algorithm, and secondly neural control of primary path based on neural model obtained in the first stage. A tapped delay line is introduced in front of controller neural, and another tapped delay line is inserted between controller neural networks and model neural networks. A new algorithm referred to as Filtered X-RBF is proposed to account for secondary path effects of the control system arising in active noise control. The resulting algorithm turns out to be the filtered-X version of the standard RBF learning algorithm. We address centralized and decentralized controller configurations and their DSP implementation is carried out. Effectiveness of the neural controller is demonstrated by applying the algorithm to active noise control within a 3 dimension enclosure to generate quiet zones around error microphones. Results of the real-time experiments show that 10-23 dB noise attenuation is produced with moderate transient response.
Dissipative Controller Design for Networked Control Systems via the Markovian Jump System Approach Najmurrokhman, Asep; Riyanto T., Bambang; Syaichu-Rohman, Arief; Hendrawan, H.
Journal of Engineering and Technological Sciences Vol 45, No 1 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (235.954 KB) | DOI: 10.5614/j.eng.technol.sci.2013.45.1.3

Abstract

This paper describes a dissipative controller design for networked control systems modeled by the Markovian jump system. Dissipativity refers to the existence of a supply rate dealing with the system such that the closed-loop system has a dissipative property. The main result of this paper is a solvability condition in terms of linear matrix inequalities for achieving dissipativity of a dynamic output feedback problem in networked control systems via the Markovian jump system approach. A numerical example is given to show the efficacy of the proposed design.
Estimation of Bank Erosion Due to Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir) Legowo, Sri; Hadihardaja, Iwan K.; Azmeri, Azmeri
Journal of Engineering and Technological Sciences Vol 41, No 2 (2009)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (619.349 KB) | DOI: 10.5614/itbj.eng.sci.2009.41.2.5

Abstract

Sedimentation  is  such  a  crucial  issue  to  be  noted  once  the accumulated  sediment  begins  to  fill  the  reservoir  dead  storage,  this  will  then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management  of  activities.  The  continuous  inflow  of  sediment  to  the  reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful  age  of  reservoir.  Because  of  that,  the  rate  of  the  sediment  needs  to  be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This  effort  can  be  performed  through;  the  regulation  of  fluctuating  rate  of reservoir surface current that does not cause suddenly  drawdown  and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP). The  rate  of  bank  erosion  for  the  reservoir  variates  from  0.0009  to  0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean  while  the   rate  of  watershed  sediment  has  a  significant  value,  i.e:  3,02  MCM/year  for  Saguling  that  causes  to  fullfill  the  storage  capacity  in  40  next years (from years 2008). 
Increased Error Observability of an Inertial Pedestrian Navigation System by Rotating IMU Abdulrahim, Khairi; Hide, Chris; Moore, Terry; Hill, Chris
Journal of Engineering and Technological Sciences Vol 46, No 2 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (407.635 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.2.7

Abstract

Indoor pedestrian navigation suffers from the unavailability of useful GNSS signals for navigation. Often a low-cost non-GNSS inertial sensor is used to navigate indoors. However, using only a low-cost inertial sensor for the system degrades its performance due to the low observability of errors affecting such low-cost sensors. Of particular concern is the heading drift error, caused primarily by the unobservability of z-axis gyro bias errors, which results in a huge positioning error when navigating for more than a few seconds. In this paper, the observability of this error is increased by proposing a method of rotating the inertial sensor on its y-axis. The results from a field trial for the proposed innovative method are presented. The method was performed by rotating the sensor mechanically–mounted on a shoe–on a single axis. The method was shown to increase the observability of z-axis gyro bias errors of a low-cost sensor. This is very significant because no other integrated measurements from other sensors are required to increase error observability. This should potentially be very useful for autonomous low-cost inertial pedestrian navigation systems that require a long period of navigation time.
Influence of High Temperatures on the Workability of Fresh Ready-Mixed Concrete Sampebulu, Victor
Journal of Engineering and Technological Sciences Vol 44, No 1 (2012)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (611.217 KB) | DOI: 10.5614/itbj.eng.sci.2012.44.1.2

Abstract

Properties of fresh concrete made in tropical countries, which is mixed, transported (with agitation), placed and initially cured in places where the temperature ranges from about 20oC to 40oC and relative humidity above 60%, are not completely understood. Applicable requirements also differ from country to country and government agencies and private enterprises have their own specifications. Assuming such temperature and relative humidity conditions, the present study is an attempt at evaluating the properties of hot weather concrete in fresh state with using a method of ready–mixed concrete. The fresh concrete was mixed and agitated at varying concrete and ambient temperatures. Three groups of the component materials, each material having such temperature as to bring resulting temperature of the fresh concrete to about 20oC, 30oC, 35oC, were chosen. The temperature of cement was conditioned to about20o, 40oC and 60oC for each of groups respectively. The aggregate was made warm enough to simulate the condition of outdoor pile in ready-mixed concrete plant. The temperature of tap water was always 20oC as it was easily controlled and unlikely affected by outdoor temperature. With the fresh concrete prevented from evaporation, slump loss is caused solely by increased temperature of concrete. During agitation, the slump loss increases rapidly during the first 30 minutes but moderately during the remaining period. Concrete-placing temperature (upon arrival at the work site) could be estimated by a proposed formula derived from this study. Besides the freshly mixed concrete temperature, this formula also takes into consideration the ambient temperature, agitating time in transit and hydration heat. The achievement as described in this study may be useful to control concrete quality in terms of strength, shrinkage and other properties of concrete to be placed in hot-humid environment.
Ground Deformation during Papandayan Volcano 2002 Eruption as Detected by GPS Surveys Abidin, Hasanuddin Z.; Andreas, H.; Gamal, M.; Sugandar, Ony K.; Meilano, Irwan; Hendrasto, M.; Kusuma, M. A.; Darmawan, D.; Purbawinata, M. A.; Wirakusumah, A. D.; Kimata, F.
Journal of Engineering and Technological Sciences Vol 35, No 1 (2003)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2964.335 KB) | DOI: 10.5614/itbj.eng.sci.2003.35.1.4

Abstract

Papandayan is an A-type active volcano located in the southern part of Garut Regency, about 70 km southeast of Bandung, Indonesia. Its earliest recorded eruption, and most violent and devastating outburst occurred in 1772 and the latest eruptions occurred in the period of 11 November to 8 December 2002, and consisted of freatic, freatomagmatic and magmatic types of eruption.During the latest eruption period, GPS surveys were conducted at several points inside and around the crater in a radial mode using the reference point located at Papandayan observatory around 10 km from the crater. At the points closest to the erupting craters, GPS displacements up to a few dm were detected, whereas at the points outside the crater, the displacements were in the cm level. The magnitude of displacements observed at each point also show a temporal variation according to the eruption characteristics. The results show that deformation during eruption tends to be local, e.g. just around the crater. Pressure source is difficult to be properly modeled from GPS results, due to limited GPS data available and differences in topography, geological structure and/or rheology related to each GPS station.
Comparison of Two Different Earthquake Sources for the 26 December 2004 Aceh Tsunami Simulation Puspito, Nanang T.; Gunawan, Indra
Journal of Engineering and Technological Sciences Vol 38, No 1 (2006)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1364.491 KB) | DOI: 10.5614/itbj.eng.sci.2006.38.1.5

Abstract

The tsunami wave propagation of the 26 December 2004 Aceh tsunami has been studied by performing a numerical tsunami simulation based on a method that was originally developed by the Tohoku University. The initial model was calculated based on the fault parameters proposed by GFZ Potsdam and Tohoku University. Despite the limitations in the numerical simulation, generally the calculated tsunami heights and arrival times show a relatively good agreement with the observed ones. Based on the simulation it can be estimated that the tsunami wave may reach the west and north coast of northern Sumatra at about 15 to 25 and 20 to 30 minutes after the earthquake, respectively. The maximum calculated tsunami heights in the west and north coast of Aceh were about 11 to 24 and 8 to 15 m, respectively. The calculated arrival times show that the tsunami wave may reach west coast of Thailand and east coast of India and Sri Lanka at about 90 to 100 and 100 to 120 minutes after the earthquake, respectively. The maximum calculated tsunami heights at Phuket of Thailand and Tricomalee of Sri Lanka were about 4 to 5 and 1.5 to 3.5 m, respectively.
Development of Intelligent Controller with Virtual Sensing Nazaruddin, Yul Y.; Astuti, Puji
Journal of Engineering and Technological Sciences Vol 41, No 1 (2009)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (497.092 KB) | DOI: 10.5614/itbj.eng.sci.2009.41.1.2

Abstract

In  many  industrial  plants,  some  key  variables  cannot  always  be measured on-line and for the purpose of control, an alternative of sensing system is  required.  This  paper  is  concerned  with  a  development  of  an  alternative intelligent  control  strategy,  which  is  an  integration  between  the  neuro-fuzzy based  controller  and  virtual  sensing  system.  This  allows  an  immeasurable variable to be inferred and used for control. The  virtual sensor is  composed of the  Diagonal  Recurrent  Neural  Network  (DRNN)  for  plant  modeling  and  the Extended  Kalman  Filter  (EKF)  as  the  estimator  with  inputs  from  DRNN.  The integration between virtual sensor and the controller enables a development of an on-line  control  scheme  involving  the  immeasurable  variable.  The  real -time implementation  demonstrates  the  applicability  and  the  performance  of  the proposed  intelligent  control  scheme,  especially  in  dealing  with  nonlinear processes.
Calcium Pectinate Beads Formation: Shape and Size Analysis Lee, Boon-Beng; Chan, Eng-Seng; Ravindra, Pogaku
Journal of Engineering and Technological Sciences Vol 46, No 1 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (351.916 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.1.5

Abstract

The aim of this study was to investigate the inter-relationship between process variables and the size and shape of pectin solution droplets upon detachment from a dripping tip as well as Ca-pectinate beads formed after gelation via image analysis. The sphericity factor (SF) of the droplets was generally smaller than 0.05. There was no specific trend between the SF of the droplets and the pectin concentration or the dripping tip radius. The SF the beads formed from high-concentration pectin solutions and a small dripping tip was smaller than 0.05. The results show that the Reynolds number and Ohnesorge number of the droplets fall within the operating region for forming spherical beads in the shape diagram, with the exception to the lower boundary. The lower boundary of the operating region has to be revised to Oh = 2.3. This is because the critical viscosity for Ca-pectinate bead formation is higher than that of Ca-alginate beads. On the other hand, the radius of the droplets and beads increased as the dripping tip radius increased. The bead radius can easily be predicted by Tate’s law equation.

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