# Special Issue: Selected Papers from IEEE ICASI 2019
###### Abstract
Two-dimensional ERT assumes that the ground condition is perpendicular to the survey line and homogeneous outside the survey line. This assumption can often be violated in conditions such as geologic strikes not being perpendicular to the survey line and topographic changes or buried objects near the survey line. Possible errors or artifacts in the 2D resistivity tomogram arising from violating the 2D assumption are often overlooked. This study aimed to numerically investigate the boundary effects on 2D ERT under various simplified conditions. Potential factors including resistivity contrast, the depth and size of buried objects, and electrode spacing were considered for the parametric studies. The results reveal that offline geologic features may project onto the 2D tomogram to a certain extent, depending on the aforementioned factors. The mechanism and implications of boundary effects can be drawn from these parametric studies. [PERSON] et al. [7] reported on \"Area-efficient FFT Kernel with Improved Use of GI for Multistandard MIMO-OFDM Applications\". This study presents a fast Fourier transform (FFT) kernel for multistandard applications, which employ multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM). The proposed design uses a mixed-radix, mixed-multipath delay-feedback (MRM2 DF) structure, which enables 4/5/6-stream 64/128-point FFT. This approach allows for the effective usage of guard intervals in conjunction with a novel resource-sharing scheme to improve area efficiency. An area-reduced constant multiplication unit and sorting buffer with minimal memory size further reduced an area overhead. A test chip was designed using UMC 90-nm technology and was evaluated through post-layout simulation. The proposed design outperformed previous works in terms of throughput per area. [PERSON] et al. [8] reported on \"The Design and Building of a Hexapod Robot with Biomimetic Legs\". A hexapod robot with biomimetic legs was built to implement a distributed control system, where a mechanism is proposed to serve as the central pattern generator and a computer to act as the brain stem, cooperating with the central pattern generator through wireless communication. The proposed mechanism consists of two modules, i.e., tripod gait generator and [PERSON]'s linkage. The tripod gait generator is a device that uses a single motor to generate a tripod gait, while [PERSON]'s linkage rhythmically executes the legged motion. In a sense, we are trying to implement the locomotion of a robot by means of a hybrid computational system, including the mechanism and electronic processor parts. The complex mathematical function of the foot movement is realized by the ensemble of links of the [PERSON]'s linkage to alleviate the computational burden. Furthermore, the proposed design,based on non-collocated actuators, is intended to minimize the number of actuators while reducing the building cost of the robot. [PERSON] et al. [9] reported on \"Heating, Ventilation, and Air Conditioning System Optimization Control Strategy Involving Fan Coil Unit Temperature Control\". The objective of this study was to develop a heating, ventilation, and air conditioning (HVAC) system optimization control strategy involving fan coil unit (FCU) temperature control for energy conservation in chilled water systems to enhance the operating efficiency of HVAC systems. The proposed control strategy involves three techniques, which are described as follows. The first technique is an algorithm for dynamic FCU temperature setting, which enables the FCU temperature to be set in accordance with changes in the outdoor temperature to satisfy the indoor thermal comfort of occupants. The second technique aims to determine the indoor cold air demand, which collects the set FCU temperature and converts it to the refrigeration ton required for the chilled water system, thereby serving as the control target for ensuring optimal HVAC operation.