Fergyanto E. Gunawan

Impact force reconstruction using the regularized Wiener filter method

There are cases in engineering applications where the involved impact forces are impractical or difficult to be directly measured. In such cases, the impact forces may inversely be reconstructed on the basis of the associated-induced elastic responses. However, the inverse impact force reconstruction is an ill-posed problem. So far, various methods have been proposed. Many require complex mathematical treatments; thus, they are impractical for experimental engineers. In this article, we adopt the Wiener filter method and introduce a regularization technique so that the method can provide an optimum solution which balances the aspects of the minimum noise and the minimum residual. The proposed method is evaluated using three examples of the impact problems. The evaluation reveals that the regularized Wiener filter method is less sensitive to the regularization parameter unlike many of the existing methods. Therefore, the method is more suitable for practical applications.

A System for Real-Time Passenger Monitoring System for Bus Rapid Transit System

TransJakarta is a BRT-based mass transportation system operating in Jakarta, the capital of Indonesia. Currently, the system delivers rather low level of service; as a result, the number of passengers is rather low in comparison to that of the other BRT-based systems. In this work, we propose a design of the passenger counting system for BRT-based system, which is very important for the BRT fleet management to increase the system level of service. The counting system is established by deploying computer vision techniques. A few algorithms are evaluated and the Adaptive Median Filtering with the sampling rate of 13 produces the highest level of precision and recall.

Attendance system on Android smartphone

Attendance system which is currently excist still has weaknesses. The first is the long queues in front of the attendace machine at the time to come to work and leave work. The second is cheating, employees can ask her/his friend to do attendance process. The third is mostly attendance system has not been connected with the payment system in human resouces software or in the finance department. The fourth, employees who work outside the office can not do attendance process. In this paper, we introduced an attendance system based finger print technology and GPS using a smartphone integrated with payment system that will eliminate all the problems above. Our research also based on prediction that in the next few year all the smart phone will have a fingerprint scanner.

Increasing the accuracy of distance measurement between access point and smartphone

This research focused on distance measurement using Received Signal Strength Indicator (RSSl) that utilizing Pythagoras theory to get the position of a smartphone with the help of 4 Access Point (AP) in indoor environment. There were many research have been done in this area, but the issue is about the accuracy. From studies that have been done before, there are differences between the results of calculation using RSSl with the actual distance with the average of 1.6 meters. Our result indicate that when calculating the distance using optimization RSSl method, we can reduce the distance difference average value between Access Point (AP) and smartphone is 0.6 meters with an accuracy of 86.1%. Coordinate measurement using Pythagoras Theory also produce average of localization error valued of 0.6 meters.

Data transmission strategy of probe vehicle in floating car traffic monitoring

The floating car data (FCD) method is an example of the applications of the Intelligent Transportation Systems (ITS) where the traffic data are provided by means of the information and communication technology. In the FCD method, the traffic data are collected, manipulated, and transmitted by probe vehicles via a wireless network to a designated server where the data are stored, manipulated, and displayed in conjunction with a digital map. The method is capable to provide near real-time traffic data but its performance strongly and mainly depends on the reliability of the wireless network. In this work, the traffic data transmission strategy in the FCD method is discussed and its effect to the timeliness of the traffic data is described. As the results, it is found that when the data transmission strategy is not properly designed, a delay in a transmitted packet of data directly affects and intensifies the subsequent data transmission. We propose a transmission strategy to minimize the time delay and experimentally demonstrate that the strategy can reduce the time delay significantly.

Statistically optimum virtual trip line for real-time traffic monitoring system

The virtual trip line (VTL) has been proposed in conjunction with the floating car data method to minimize the potential breach of the probe vehicle privacy. However, a long VTL, as well as a short one, may have unintended consequences; thus, the VTL length should be optimized. This article intends to propose a method to establish the optimum length of the VTL. The optimal length of VTL is determined empirically based on the geo-location data collected by ten units of smart-phones. A custom-made application is designed and installed to these devices to track and record the movement of the probe vehicle. The recorded geolocation data are projected to the road GIS line to establish the projection distances. We demonstrate that the distances are distributed approximately following the normal distribution, from which the critical region of the optimum VTL length for a given significance level is established. Finally, we empirically evaluate the method, and demonstrate that for a given VTL length, the empirical probability of the probe vehicle crossing a VTL is close to the theoretical probability.

The impact of e-Procurement practice in Indonesia government: A Preliminary Study (The case of Electronic Procurement Service at Bekasi District)

In digital economy, government of Indonesia uses the internet to deliver services and to communicate with citizens and organizations. One of applications are e-Procurement and LPSE is a unit to hold the service system of e-Procurement. Procurement of goods and services electronically in addition will increase transparency and accountability, improve market access and healthy competition, as well as improving the efficiency of the procurement process. Based on the background and specific objectives to be achieved, then the research will be viewed from e-Marketplace participation, Trust and its impact on the performance of existing procurement within the institution. Methods of data analysis used in this research is by using analysis of Structural Equation Modelling (SEM) by using the program Partial Least Square (PLS) to examine the relationship between variables. The population used in this study is an enterprise as well as other clients using the system LPSE Bekasi District. There are three part in this study population, namely the provision of a company, customer, and supplier of LPSE users amounted to 60 users. From data analysis, there are one hypothesis that rejected. The implication of this study are implementation of e-procurement and e-marketplace participation giving impact to procurement performance.

Improvement of E-learning quality by means of a recommendation system

Technology Enhanced Learning is one of the most dynamic areas of inquiry in education. One form of TELs, that is on-screen learning, has been well understood to hinder learning experience due to the reading spatial instability, difficulties in establishing mental map, and poor visual ergonomics. This work intends to study to which extend a learning a recommendation system improving on-screen learning experience. Participants were randomly divided into two groups: one group learning with the learning recommendation system and the other is without the system. Their understanding were assessed and a t-test was performed. The results indicated that the average score of learning with the recommendation system was significantly higher and the detrimental effects were mitigated.

Detecting online child grooming conversation

Massive proliferation of social media has opened possibilities for perpetrator to conduct the crime of online child grooming. Because the pervasiveness of the problem scale, it may only be tamed effectively and efficiently by using an automatic grooming conversation detection system. Previously, Pranoto, Gunawan, and Soewito [1] had developed a logistic model for the purpose and the model was able to achieve 95% detection accuracy. The current study intends to address the issue by using Support Vector Machine and fc-nearest neighbors classifiers. In addition, the study also proposes a low-computational cost classification method on the basis of the number of the existing grooming conversation characteristics. All proposed methods are evaluated using 150 conversation texts of which 105 texts are grooming and 45 texts are non-grooming. We identify that grooming conversations possess 17 features of grooming characteristics. The results suggest that the SVM and fc-NN are able to identify grooming conversations at 98.6% and 97.8% of the level of accuracy. Meanwhile, the proposed simple method has 96.8% accuracy. The empirical study also suggests that two among the seventeen characteristics are insignificant for the classification.

Power consumption for security on mobile devices

In order to avoid intruder steals sensitive information over the network, one thing that we may consider is to encrypt the sensitive information beside install an antivirus on the devices or networks. The problem is the strong encryption algorithm is very complex and required intensive computational that need huge power consumption and others resources in mobile devices. Furthermore, people have been using mobile devices to transfer the important information or doing commercial transactions. In this case, security is an important issue to protect the sensitive information, but in the other hand, the portable or mobile devices powered by battery that have limitation in battery lifetime. Choosing the suitable encryption-decryption algorithm to implement in the mobile devices is one of the important decisions to secure exchanging sensitive information with constraining of this source of power. In this research, We evaluate the power consumption of four Advanced Encryption Standard (AES) finalist: RC6, Serpent, Mars, and twofish with respect to the size of file using Joulemeter, PassMark BatteryMon, and Wattch. Our research showed that the Twofish algorithm is the least amount of energy to encrypt the data and the Serpent algorithm is the most need energy to encrypt the data.