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IPTEK The Journal for Technology and Science
Published by Institut Teknologi Sepuluh Nopember Surabaya
ISSN : 08534098     EISSN : 20882033     DOI : -
Core Subject : Science,
Computer Science & IT
IPTEK The Journal for Technology and Science (eISSN: 2088-2033; Print ISSN:0853-4098), is an academic journal on the issued related to natural science and technology. The journal initially published four issues every year, i.e. February, May, August, and November. From 2014, IPTEK the Journal for Technology and Science publish three times a year, they are in April, August and December in online version.
Arjuna Subject : -
Articles 345 Documents
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Numerical Study of Mixed Convection in A Cooled Room Dedy Zul Hidayat Noor; Heru Mirmanto; Eddy Widiyono; liza rusdiyana
IPTEK The Journal for Technology and Science Vol 26, No 1 (2015)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v26i1.570

Abstract

The present work is carried out to study laminar mixed convection heat transfer inside a rectangular cooled room numerically. The chosen model is considered as a representation of a room facing the sun with a floor releasing heat resulted by electronic components or human activities. The Reynolds number and Richardson number are varied from 100 to 400 and 0 to 3, respectively, in order to cover laminar mixed convection phenomena. For the considered range of Re dan Ri, the flow regimes fall into  three modes. The higher Nusselt numbers are found at the higher values of Re, on the other hand, the forced convection leads to higher heat transfer rate than the free/natural convection.
Determining the Characteristics of Trips Generated on Southern Bali using Category Analysis I Wayan Suweda; Achmad Wicaksono; Indrasurya Budisatria Mochtar
IPTEK The Journal for Technology and Science Vol 22, No 4 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i4.78

Abstract

Southern Bali, a tourism center of Indonesia, has been rapidly developed. Unfortunately, the development is not followed simultaneously by the development of adequate transportation network, as a result, traffic congestion are inevitably occurred along every urban road in the district. Therefore integrated development and regional transport planning therefore, is urgently required. In this study, trip generation is determined using Category Analysis. It is Figured out from the household based interview that Denpasar Barat zones are found to have the largest trip generation while Pecatu zones are found to be the smallest. Most of the household trips generated use private vehicles (94.95%) and the rest uses public transport. This also indicates that public transport services in Southern Bali still need to be developed.
Simulation Characteristics Continous Variable Transmission of Motor Cycle using Torque Control Based Fuzzy Logic Ary Subagya; I.K.A. Atmika
IPTEK The Journal for Technology and Science Vol 20, No 1 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i1.132

Abstract

CVT is gear less transmission that was implemented on the motor cycle, it is purpose to increase handling of vehicle. In this case, gear less transmission developed by traction control using the fuzzy logic controller from the Mat-Lab soft wear. It modelled by simulation with gear ratio, speed, and traction toward acceleration (a), time (t), distance (s), and grade ability (G). The conclusion, the characteristic of torque control on gear less transmission of vehicle was increase handling toward acceleration (a), time (t), distance (s), and grade ability (G).
Nested Generalized Linear Model with Ordinal Response for Correlated Data Yekti Widyaningsih; Asep Saefuddin; Khairil A. Notodiputro; Aji H. Wigena
IPTEK The Journal for Technology and Science Vol 23, No 2 (2012)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v23i2.12

Abstract

In this paper, we discuss the generalized linear models with ordinal response for correlated data in nested area. Some basic concepts are described, that is nested spatial, threshold model, and cumulative link function. Due to correlated data used for this modeling, Generalized Estimating Eequation (GEE) is used as model parameters estimation method. Nested is shown by the model building and its application on nested spatially data. In this method, some Working Correlation Matrices (WCM) are able to be specified depend on the nature and type of the data. In this study, 3 types of WCM and 2 types of parameters estimation covariance are used to see the results of parameters estimation from these combinations. As a conclusion, independent WCM is appropriate to the data.
Application of Adaptive QAM Modulation and Diversity Scheme for 30 GHz Cellular Communications under the Impact of Rain Attention in Indonesia Gamantyo Hendrantoro; Achmad Mauludiyanto; Ninik D. Yundariani
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.167

Abstract

In millimeter-wave wireless cellular systems like Local Multipoint Distribution Services (LMDS) rain attenuation is an essential factor of performance degradation. It can cause signal outages and poor quality of signal reception. To mitigate the problem, a combination of diversity and adaptive modulation is proposed. To investigate the impact of the use of these techniques, a simulation is performed for a 30 GHz cellular system to obtain SNR (signalto- noise ratio), diversity gain, modulation level and BER (bit error rate). Analysis of the implementation of the combined techniques is accomplished by taking into account such factors as length of links and the combining method Simulation results show that diversity can improve the overall system SNR. Diversity gain of up to 15 dB can be achieved on two 4-km converging links at 0.01% outage probability when maximal-ratio combining (MRC) is used. For systems with luxurious link design for which the clearsky SNR is more than 30 dB, as considered in this paper, diversity and adaptive modulation do not significantly contribute to improvement of achievable transmission rate and BER performance. However, for systems with lower values of clear-sky SNR, use of both techniques will be more worthwhil.
Web-Based Tsunami Early Warning System Daniel Siahaan; Royke Wenas; Amien Widodo; Umi Yuhana
IPTEK The Journal for Technology and Science Vol 24, No 3 (2013)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v24i3.552

Abstract

Tsunami is a serious threat to the island nation such as Indonesia. The tsunami disasters that were occurred in some parts of Indonesia have immerged the need for tsunami early warning system that is reliable and can be applied to the Indonesian archipelago. North Sulawesi is one of the areas prone to tsunamis since this area lies in the path called the ring of fire's. This article describes a tsunami simulation application for the north coast of North Sulawesi. Web-based applications were built so that they can be monitored online from anywhere and at anytime. This system reads the real-time seismic data that affect the North Sulawesi region from a number of sources. Dynamic and static data that are received are processed using data mining method to predict the chances of a tsunami, while flood flooding algorithm is used to visualize the map of affected areas of North Sulawesi. The resulting information is available in detail in the form of web pages and also through short message to the relevant authorities handling of the tsunami disaster in order for them to act in accordance with applicable standard operating procedures. With this application, the public can obtain information that is more accurate. Relevant authorities can conduct tsunami disaster mitigation measures more effectively.
Minimum Constructive Back Propagation Neural Network Based on Fuzzy Logic for Pattern Recognition of Electronic Nose System Radi Radi; Muhammad Rivai; Mauridhi Hery Purnomo
IPTEK The Journal for Technology and Science Vol 22, No 3 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i3.69

Abstract

Constructive Back Propagation Neural Network (CBPNN) is a kind of back propagation neural network trained with constructive algorithm. Training of CBPNN is mainly conducted by developing the network’s architecture which commonly done by adding a number of new neuron units on learning process. Training of the network usually implements fixed method to develop its structure gradually by adding new units constantly. Although this method is simple and able to create an adaptive network for data pattern complexity, but it is wasteful and inefficient for computing. New unit addition affects directly to the computational load of training, speed of convergence, and structure of the final neural network. While increases training load significantly, excessive addition of units also tends to generate a large size of final network. Moreover, addition pattern with small unit number tends to drop off the adaptability of the network and extends time of training. Therefore, there is important to design an adaptive structure development pattern for CBPNN in order to minimize computing load of training. This study proposes Fuzzy Logic (FL) algorithm to manage and develop structure of CBPNN. FL method was implemented on two models of CBPNN, i.e. designed with one and two hidden layers, used to recognize aroma patterns on an electronic nose system. The results showed that this method is effective to be applied due to its capability to minimize time of training, to reduce load of computational learning, and generate small size of network.
The Influence of Mason Group Composition on Optimal Field Labor’s Productivity in Malang – East Java Tjaturono Tjaturono
IPTEK The Journal for Technology and Science Vol 20, No 3 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i3.111

Abstract

The composition of labor groups is one of the main factors determining their productivity. So far, in Indonesia the labor composition is based on both the Indonesian National Standard (Standar Nasional Indonesia/ SNI) of 2001 and the result of housing developers’ 'trial and error test'. However, these compositions do not produce an optimal productivity. This study is aimed at obtaining an ideal composition of a labor group and equivalent coefficient as well as actual productivity differences on productivity of the SNI 2001. The method used are field observation and interview on 260 labors from a group of the middle-class house's construction in Malang – East Java. The data obtained were processed by using descriptive statistics and statistical test for mean differences. The results of this research show that the ideal compositions of masonry foundation and bricklaying labors are: 1 mason: 2 labors, and 1 mason: 1½ labors for wall plastering. The equivalent coefficients for various mason groups are also obtained. Compared with the actual productivity of SNI 2001, the field labors’ productivities are 108, 5%, 19%, and 155% for masonry foundation, bricklaying, and wall plastering, respectively
Development of Ultra-Carbon Steel Prepared by Mechanical Alloying and Subsequent Hot Pressing Nurul T. Rochman; H. Sueyoshi
IPTEK The Journal for Technology and Science Vol 19, No 1 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i1.158

Abstract

It is known that the most effective way to improve mechanical properties of steels is by microstructural refinement. Iron and graphite powders mixture with hypoeutectoid composition were mechanically alloyed (MAed) and subsequently hot pressed (HPed) to provide steels with fine structure. Mechanical Alloying (MA) was carried out using a planetary ball mill for 100, 200 and 300 h, while HP at 41 MPa at various temperatures: 610ºC (below), 730ºC (near) and 800ºC (above the eutectoid transformation point A1). The mechanically alloyed (MAed) powders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). While, the HPed compacts were characterized by SEM, Vickers hardness and tensile test. During MA, refinement of crystallite, formations of super-saturated iron solid solution and Fe/C amorphous phase occured first. With further MA time, these phases might begin to transform to more stable phases such as carbides. In the case of HP at 610ºC (below A1), very fine cementites were precipitated in fine ferrite grain with sub-micron meter in the size. However, the mechanical properties cannot be attained because of low sinterability. At 730ºC (near A1), the strength reaches the maximum value. With further temperature increase (at 800ºC), the sintering progressed well and the coarsening occured, resulting the decrease in strength. However, the fracture strain increased significantly. The steels obtained in the present study had mechanical properties comparable to those of standard (JIS) steels through the welle stablished heat treatment such as normalizing and thermal refining.
On the Development of a Vibration Energy Harvesting Mechanism and the Influence of the Number of Wire Turns Wiwiek Hendrowati; Bambang Daryanto W Daryanto W; I Nyoman Sutantra
IPTEK The Journal for Technology and Science Vol 21, No 2 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i2.35

Abstract

This article deals with a research activity to design and to build a vibration energy harvesting (VEH) mechanism based on an electromagnetic method, where the energy source is from translational-harmonic vibration. In the developed VEH mechanism, a magnetic mass moves linearly back and forth within an electrical coil made from conductive-wire windings. In accordance to oscillating mass motion of a particular amplitude and frequency, the voltage which can be harvested is then measured and analyzed. The choice of an electromagnetic method stemmed from the availability of materials to construct the VEH mechanism. In the VEH mechanism, a mass size, a wire diameter and material, a coil length, and a vibration amplitude and frequency were considered constant, while the number of wire turns was varied. The constructed VEH was tested for 1,000, 1,500, 2,000, 2,500, and 3,000wire turns. The voltage density being harvested was recorded as 0.2820, 0.3715, 0.5695, 0.7343 and 0.9300 volt/cm3, respectively.

Page 11 of 35 | Total Record : 345

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