Eko Setijadi

Bio: Eko Setijadi is an academic researcher from Sepuluh Nopember Institute of Technology. The author has contributed to research in topics: Antenna (radio) & Microstrip antenna. The author has an hindex of 7, co-authored 98 publications receiving 261 citations. Previous affiliations of Eko Setijadi include Kumamoto University.

Effect of temperature and multiple scattering on rain attenuation of electromagnetic waves by a simple spherical model

Abstract: Speciflc rain attenuation is discussed from the viewpoint of numerical solution for scattering and absorption of electromagnetic waves related to dielectric spheres. Special attention is paid to the quantitative evaluations considering the change of temperature and the existence of multiple scattering efiect. The analysis is based on the set of Stratton's vector spherical wave functions and its addition theorem, which lead to the simultaneous linear equations for the expansion coe-cients with adaptively selected truncation numbers. Computed extinction cross sections lead directly to the speciflc rain attenuation, where the Weibull raindrop distribution model is used. It is discussed how the dependence of the permittivity of water on temperature and frequency afiects the attenuation property. Furthermore, the efiect of multiple scattering is evaluated in terms of the root mean square of attenuation deviation from the simple superposition of single scattering (Mie's) coe-cients. Contrary to general belief, this deviation is the highest at around the boundary between microwave and millimeter wave bands.

Mutual Coupling Reduction for a UWB Coplanar Vivaldi Array by a Truncated and Corrugated Slot

Abstract: This letter reports mutual coupling reduction in an ultrawideband coplanar Vivaldi array (CVA) by incorporating truncated and corrugated slot at the border between adjacent elements. An examination of CVAs shows that mutual coupling in the E-plane is more significant than in the H-plane. Subsequently, arrays using exponential and rectangular corrugated slot are compared with those without a slot structure through the simulation of a surface current distribution. A novel exponential corrugated truncated (ECT) structure is implemented to improve a mutual coupling performance, while maintaining or even improving copolar field patterns. The results of simulation and measurement indicate that mutual coupling and return loss performance can be improved by controlling the length of corrugated structure and the distance of the slot structure from the center of the Vivaldi's tapered slot. The CVA achieves bandwidth ratio of 5:1, i.e., from 2 to 10 GHz. The ECT-CVA structure reduces mutual coupling to below −20 dB in a large portion of the whole band, shows 3.9–10.2 dBi gain over the entire band, increases a sidelobe level performance at 4–9 GHz compared to the CVA without slot structure.

A Model for Evaluation Smart City Readiness using Structural Equation Modelling: a Citizen's Perspective

Abstract: Smart City is the use of ICT-based governance and cloud is now a trend throughout the world. Various increasingly complex city problems are expected to become increasingly more efficient by applying the concept of smart cities in city governance. However, in its implementation, many crucial problems significantly affect the success of the implementation of smart cities, including the lack of competent human resources, ICT policies and governance that have not been efficient, lack of government commitment and the lack of community participation. This study aims to model smart city readiness factors in community perspectives. The method in this study is quantitative descriptive research using a combination of the Technology Readiness Index model, the Technology Acceptance Model and the Delone McLean Model. Data collection is done by conducting surveys and interviews with 200 citizens. Data analysis using Structural Equation Modeling with the help of AMOS 23.0 software. The results showed that there were a significant relationship and relevance between the variables in the model used in the TRI, TAM and Delone McLean models. This study contributes to the relationship modelling of the factors that determine the success of applying the smart city concept. This research provides recommendations to the government and stakeholders to pay more attention to the crucial factors in the success of developing smart cities.

Performance of the routing protocols AODV, DSDV and OLSR in health monitoring using NS3

Abstract: The complexity of health care and the increasing cost of health care in developing country such as Indonesia caused by the source of available funds and limited human resources, especially health professionals. Health monitoring through wireless body area network is one of the solution and which offers several advantages as inexpensive health services, better utilization from health care professional resource, mobility, and great experience for the patient. However, health monitoring has some challenges such as limited area coverage, mobility problem and attenuation from human body. In this paper, it describes how to research about utilization AODV, DSDV, and OLSR routing protocols from ad hoc network to improve health monitoring by using NS3 to face limited area coverage and mobility problem for static and mobile conditions. As simulation, the researcher compares the performance of AODV, DSDV, and OLSR. The researcher selected three performances of metrics: delay, throughput, and packet delivery ratio. As a result showed, OLSR has better performance for mobile and mobile has more than 50 nodes except delay, when througput, and packet delivery ratio of mobile condition OLSR show better than AODV. In static condition, throughput of AODV shows better than DSDV and OLSR, even though for mobile condition OLSR shows better than AODV and DSDV, but in some cases the delay of AODV shows better than DSDV and OLSR. This is an indication for the possible implementation of OLSR routing protocols which node is bigger than 50 nodes.

Design of 2.4 GHz Slotted SIW Array Antenna for WLAN Application

Abstract: This paper deals with the design of 2.4 GHz slotted substrate integrated waveguide (SIW) array antenna for wireless local area network (WLAN) application. The use of SIW structure is addressed to achieve a compact shape of waveguide-based array antenna especially at low frequency region. The proposed array antenna which is intended to work at the frequency of 2.4 GHz applies several configurations of longitudinal slot array on an SIW surface. A 1.6 mm thick FR4 epoxy dielectric substrate is used to deploy the design of SIW-based slotted waveguide array antenna. The performances of array configuration as well as the effect of slots number are investigated to attain the specified requirement. A 4.8 dBi gain could be achieved by a 1 × 2 slotted waveguide array antenna which has 8 slots in each array configuration.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fuel Cell Electric Vehicles—A Brief Review of Current Topologies and Energy Management Strategies

Abstract: With the development of technologies in recent decades and the imposition of international standards to reduce greenhouse gas emissions, car manufacturers have turned their attention to new technologies related to electric/hybrid vehicles and electric fuel cell vehicles. This paper focuses on electric fuel cell vehicles, which optimally combine the fuel cell system with hybrid energy storage systems, represented by batteries and ultracapacitors, to meet the dynamic power demand required by the electric motor and auxiliary systems. This paper compares the latest proposed topologies for fuel cell electric vehicles and reveals the new technologies and DC/DC converters involved to generate up-to-date information for researchers and developers interested in this specialized field. From a software point of view, the latest energy management strategies are analyzed and compared with the reference strategies, taking into account performance indicators such as energy efficiency, hydrogen consumption and degradation of the subsystems involved, which is the main challenge for car developers. The advantages and disadvantages of three types of strategies (rule-based strategies, optimization-based strategies and learning-based strategies) are discussed. Thus, future software developers can focus on new control algorithms in the area of artificial intelligence developed to meet the challenges posed by new technologies for autonomous vehicles.

Construction automation and robotics for high-rise buildings over the past decades: A comprehensive review

Abstract: Automation and robotics technology is expected to improve the productivity of the construction industry as well as to solve problems such as labor shortage and safety risks, especially for high-rise buildings. Substantial research efforts have been devoted to the field over the past decades, while the application rate at the construction sites is still limited. Although various reviews have summarized the research topics and future trends in this field, few research efforts have been made on a consideration of both academic research and practical application in the industry. Focusing on high-rise building construction, this study explores the development of both academic research and practical application of automation and robotics based on literature and market review. Scientometric and critical literature reviews were conducted to identify and analyze the development of key research areas based on academic publications from the 1980s to present. In the meantime, the development of basic technologies was summarized. The market review surveyed on existing products and developers of construction automation and robotics. By comparing the results of the literature review and market review, four development patterns of academic research and product application were identified, i.e., simultaneous development led by the same party, development at a similar pace with the two sides taking the lead in different aspects, academic research providing basic technologies for product development, and available technologies in academic research with no products found. Then three gaps in this field, i.e., the gap between academic research and products, the gap between products and application, and the gap between the construction industry and the robotics industry, were discussed with corresponding suggestions to narrow the gaps, followed by an outlook for future directions. This study contributes to the knowledge body by identifying and analyzing the key research areas and the development gaps systematically.