Heru Suhartanto

Detecting and locating a singular point in the numerical solution of IVPs for ODEs

Many authors have worked on approaches for solving Initial Value Problems (IVPs) in Ordinary Differential Equations (ODEs) whose solutions contain one or more singular points within the interval of integration. Their approaches, however, assumed that the user knows in advance that the problem is singular. Hence they introduced new formulas to cope with this difficulty. In this paper, a new approach to detect and locate a singularity is suggested. This approach, which does not require the changing of the underlying formula, is comprised of two stages. The first is a preliminary singularity detection stage. The second stage is the confirmation stage which gathers more information about the existence and location of the singular point. We justify the first state and introduce three different techniques for confirming the existence of a singularity. The numerical results show that our approach is effective.ZusammenfassungEs gibt eine Reihe von Ansätzen zur numerischen Behandlung von Anfangswertproblemen für gewöhnliche Differentialgleichungen, deren Lösungen eine oder mehrere singuläre Stellen im Integrationsintervall enthalten. Diese Ansätze nehmen jedoch an, daß der Benutzer im voraus weiß, daß das Problem singulär ist; es werden deshalb neue Formeln eingeführt, die auf diese Schwierigkeiten zugeschnitten sind. In unserer Arbeit wird ein neuer Zugang zur Erkennung und Lokalisierung einer Singularität vorgeschlagen. Er erfordert keine Veränderung der zugrundeliegenden Integrationsformel und besteht aus zwei Stufen. Die erste Stufe dient zum Hinweis auf eine vermutete Singularität. Die zweite Stufe, die mehr Information bezüglich der Existenz und Lage der Singularität aufbaut, dient der Bestätigung des Vorhandenseins. Wir begründen unsere erste Stufe und geben drei verschiedene Techniken zur Bestätigung des Vorhandenseins an. Die numerischen Ergebnisse zeigen die Wirksamkeit unseres Vorgehens.

Initial Model of Indonesian e-Government Grid Services Topology

Information and Communication Technology (ICTs) is growing rapidly due to human needs for communication and fast access to information. This brought a new awareness around the world to create good governance and clean government. This is known as public management reform, called e-Government (e-Gov). Interoperability is a key issue in implementing an e-Government system. Grid-based services for interoperability (e-Government Grid) could be a solution for resource sharing and interoperability of e-Gov systems. This research is the result of Indonesian government e-Government policy study and modelling an intial e-Government Grid Services Model Topology in Indonesia which aims to create good and clean governance.

Virtual screening of Indonesian herbal database as HIV-1 reverse transcriptase inhibitor

HIV-1 (Human immunodeficiency virus type 1) is a member of retrovirus family that could infect human and causing AIDS disease. AIDS epidemic is one of most destructive diseases in modern era. There were more than 33 million people infected by HIV until 2010. Various studies have been widely employed to design drugs that target the essential enzymes of HIV-1 that is, reverse transcriptase, protease and integrase. In this study, in silico virtual screening approach is used to find lead molecules from the library or database of natural compounds as HIV-1 reverse transcriptase inhibitor. Virtual screening against Indonesian Herbal Database using AutoDock4 performed on HIV-1 reverse transcriptase. From the virtual screening, top ten compounds were mulberrin, plucheoside A, vitexilactone, brucine N-oxide, cyanidin 3-arabinoside, alpha-mangostin, guaijaverin, erycristagallin, morusin and sanggenol N.

Parallel iterated methods based on variable step-size multistep Runge-Kutta methods of Radau type for stiff problems

In our previous paper [3], the performance of a variable step‐size implementation of Parallel Iterated Methods based on Multistep Runge–Kutta methods (PIMRK) is far from satisfactory. This is due to the fact that the underlying parameters of the Multistep Runge–Kutta (MRK) method, and the splitting matrices W that are needed to solve the nonlinear system are designed on a fixed step‐size basis. Similar unsatisfactory results based on this method were also noted by Schneider [12], who showed that the method is only suitable when the step‐size does not vary too often. In this paper, we design the Variable step‐size Multistep Runge–Kutta (VMRK) method as the underlying formula for Parallel Iterated methods. The numerical results show that Parallel Iterated Variable step‐size MRK (PIVMRK) methods improve substantially on the PIMRK methods and are usually competitive with Parallel Iterated Runge–Kutta methods (PIRKs).

Advanced targets association based on GPU computation of PHD function

The precise and quick association of targets is one of the main challenging tasks in the signal processing field of the Multistatic Radar System (MRS). The paper deals with target association techniques based on the computation of the Probability Hypothetic Density (PHD) Function. The Computation time makes solving the PHD a very demanding task. The speedup of a newly developed algorithm depends on vectorization and parallel processing techniques. This paper describes the comparison between the original and parallel version of the target association algorithm with the full set of input data (without any knowledge about the approximation of targets direction) and the comparison with the advanced target association algorithm using additional input information about the direction of the target. All algorithms are processed in the MATLAB environment and Microsoft Visual Studio - C. The comparison also includes Central Processor Unit (CPU) and Graphics Processor Unit (GPU) version of all algorithms.

E-Government Grid Services Topology Based On Province And Population In Indonesia

The e-Government Grid Service Model in Indonesia is an adjustments based on the framework of existing e-Government and also the form of government in the country. Grid-based services for interoperability could be a solution for resource sharing and interoperability of e-Government systems. In previous study, we designed and simulated the topology of Indonesian e-Government Grid services based on function group from e-Government application solution map to connect the ministry/agency/department /institution. In this paper we analyse the result of e-Government services topology simulation based on the province and population in the country.

Design of intelligent k-means based on spark for big data clustering

The growth of data has bring us to the big data generation where the amount of data cannot be computed using conventional environment. There are a lot of computational environment that had been developed to compute big data, one of them is Hadoop that has Distributed File System and MapReduce framework. Spark is newly framework that can be combined with Hadoop and run on top of it. In this paper, we design intelligent k-means based on Spark for big data clustering. Our design is using batch of data instead using original Resilient Distributed Dataset (RDD). We compare our design with the implementation that using original RDD of data. Result of experiment shows that implementation using batch of data is faster than the implementation using original RDD.

Towards an environment supporting resilience, high-availability, reproducibility and reliability for cloud applications

This paper presents a design study of an environment that would provide for resilience, high-availability, reproducibility and reliability of Cloud-based applications. The approach involves the use of a resilient container overlay, which provides tools for tracking and optimizing container placement during the course of a scientific experiment execution. The system is designed to detect failure and current performance bottlenecks and be capable of migrating running containers on the fly to servers more optimal for their execution. This work is in the design phase and therefore in this paper, we outline the proposed architecture of system and identify existing container management and migration tools that can be used in the implementation, where appropriate.

Targets detection analysis in the passive coherent location system in single frequency network

The paper deals with the primary analysis of the target detection in the Passive Coherent Location system that exploits DVB-T transmitters in a Single Frequency Network. The analysis is based on the behavior of a Cross Ambiguity function and is done for one/more targets in one bistatic radar. The Single Frequency Network system uses the same central carrier frequency for all transmitters. The analysis shows that multipath effect significantly influences the determination of the precise accuracy of the maximum of the CA function.

Enhanced tele ECG system using Hadoop framework to deal with big data processing

Indonesia has high mortality caused by cardiovascular diseases. To minimize the mortality, we build a tele-ecg system for heart diseases early detection and monitoring. In this research, the tele-ecg system was enhanced using Hadoop framework, in order to deal with big data processing. The system was build on cluster computer with 4 nodes. The server is able to handle 60 requests at the same time. The system can classify the ecg data using decision tree and random forest. The accuracy is 97.14% and 98,92% for decision tree and random forest respectively. Training process in random forest is faster than in decision tree, while testing process in decision tree is faster than in random forest.