Comparison of Hysteresis Based PWM Schemes ΔΣ-PWM and Direct Torque Control

This paper presents the differences and similarities of ΔΣ-PWM as a hysteresis-based PWM scheme with direct torque control (DTC) using simulation models. The variable switching frequency caused by the hysteresis element is examined with regard to its instantaneous values. The comparison is based on an equal maximum switching frequency as a design criterion. With this first assumption, the variation of the instantaneous switching frequency is higher when using DTC because of the temporary prioritization of one inverter leg. Besides the lower variation, ΔΣ-PWM shows a higher average switching frequency. Because the switching frequency is related to the torque ripple, the usage of ΔΣ-PWM results in a smaller torque ripple. Due to the dependence of torque ripple on switching frequency, a second comparison is carried out based on the same average switching frequency. In this comparison the ΔΣ-PWM shows higher torque ripple than DTC.

Penentuan Lokasi Fasilitas untuk Meminimalkan Total Jarak Peralatan untuk Mengevakuasi Area Longsor

Dinas Pekerjaan Umum dan Penataan Ruang (PUPR) Kabupaten Pacitan berencana akan membangun 3 Unit Pelaksana Teknis (UPT) untuk meningkatkan kesiapsiagaan terhadap tanah longsor, kemudahan akses informasi publik dan pengawasan terhadap tugas-tugas dinas. Tujuan yang ingin dicapai adalah dekat dengan semua penjuru arah Kabupaten Pacitan dengan permintaan spesifik berupa desa. Lokasi kandidat untuk pembangunan UPT berjumlah 73 desa yang dinilai bisa dibangun fasilitas dari 171 titik yang merupakan total desa di Kabupaten Pacitan. Penelitian ini menggunakan metode P-Center dan Algoritma Evolusi dengan fungsi objektif meminimalkan jarak maksimum. Berdasarkan output algoritma evolusi, terdapat 4 alternatif dengan nilai jarak maksimum yang sama, yaitu 28,265 km, sehingga alternatif dipilih berdasarkan total jarak. Alternatif terpilih adalah Desa Sempu, Ngadirojo, dan Punung, dengan total jarak 2.235,583 km. Dinas Pekerjaan Umum dan Penataan Ruang (PUPR) – Kabupaten Pacitan, plans to build 3 Unit Pelaksana Teknis (UPT) to improve pre-disaster management for landslides, facilitate access to public information and oversee official duties. The goal of the three UPTs is to be close to all villages in Pacitan Regency which consider to landslide dangerous area. There are 73 villages which fulfill the requirements as location of UPT to support 171 villages in Pacitan Regency. This study uses the PCenter method and Evolution Algorithm to maximize the coverage areas. The result presents 4 alternatives give the equal maximum coverage distance (28,265 km), therefore the selection of best solution is based on the minimum total distance. The three location for UPT should be in Sempu, Ngadirojo, and Punung with a total distance of 2,235,583 km.

Capturing an Evader Using Multiple Pursuers with Sensing Limitations in Convex Environment

A modified continuous-time pursuit-evasion game with multiple pursuers and a single evader is studied. The game has been played in an obstacle-free convex environment which consists an exit gate through which the evader may escape. The geometry of the convex is unknown to all players except pursuers know the location of the exit gate and they can communicate with each other. All players have equal maximum velocities and identical sensing range. An evader is navigating inside the environment and seeking the exit gate to win the game. A novel sweep-pursuit-capture strategy for the pursuers to search and capture the evader under some necessary and sufficient conditions is presented. We also show that three pursuers are sufficient to finish the operation successfully. Non-holonomic wheeled mobile robots of the same configurations have been used as the pursuers and the evader. Simulation studies demonstrate the performance of the proposed strategy in terms of interception time and the distance traveled by the players.

Spatially tuned normalization explains attention modulation variance within neurons

Spatial attention improves perception of attended parts of a scene, a behavioral enhancement accompanied by modulations of neuronal firing rates. These modulations vary in size across neurons in the same brain area. Models of normalization explain much of this variance in attention modulation with differences in tuned normalization across neurons (Lee J, Maunsell JHR. PLoS One 4: e4651, 2009; Ni AM, Ray S, Maunsell JHR. Neuron 73: 803–813, 2012). However, recent studies suggest that normalization tuning varies with spatial location both across and within neurons (Ruff DA, Alberts JJ, Cohen MR. J Neurophysiol 116: 1375–1386, 2016; Verhoef BE, Maunsell JHR. eLife 5: e17256, 2016). Here we show directly that attention modulation and normalization tuning do in fact covary within individual neurons, in addition to across neurons as previously demonstrated. We recorded the activity of isolated neurons in the middle temporal area of two rhesus monkeys as they performed a change-detection task that controlled the focus of spatial attention. Using the same two drifting Gabor stimuli and the same two receptive field locations for each neuron, we found that switching which stimulus was presented at which location affected both attention modulation and normalization in a correlated way within neurons. We present an equal-maximum-suppression spatially tuned normalization model that explains this covariance both across and within neurons: each stimulus generates equally strong suppression of its own excitatory drive, but its suppression of distant stimuli is typically less. This new model specifies how the tuned normalization associated with each stimulus location varies across space both within and across neurons, changing our understanding of the normalization mechanism and how attention modulations depend on this mechanism. NEW & NOTEWORTHY Tuned normalization studies have demonstrated that the variance in attention modulation size seen across neurons from the same cortical area can be largely explained by between-neuron differences in normalization strength. Here we demonstrate that attention modulation size varies within neurons as well and that this variance is largely explained by within-neuron differences in normalization strength. We provide a new spatially tuned normalization model that explains this broad range of observed normalization and attention effects.