Electrical and Computer Engineering

The effect of outages in transmission lines and generator units can be predictable for stable and reliable operation of power system through contingency assessment. Hence, contingency assessment is an important task for stable and effective operation of power system. In this paper, a method of placement of interline power flow controller (IPFC) based on the probability of severity has been proposed. Contingency ranking of lines has been done using Composite Severity Index which is a probabilistic based strategy for the placement of IPFC. IPFC is placed on the line with highest probability of severity during the occurrence of different outages. Thereafter, the size of the IPFC was optimized using cuckoo search algorithm. The proposed methodology has been applied on the IEEE 14 bus system data and results presented. The system overall CSI, active and reactive power were reduced by 7.31%, 10.17% and 14.46% respectively. The results show that optimal placement of IPFC effectively reduce...

In order to have stable and improve efficiency in power supply, there is need to analyse and understand the complex interrelated factors affecting the efficiency and stability of power supply. The factors that affect the efficacy and stability of power supply in any developing country/region could be classified as follows: government policy; economy factor; natural factor; society/community factor; effective energy management; skilled personnel; efficient technology and security factor. All these factors mentioned above have direct or indirect influence on the stability and efficiency of power supply. Various numbers of complicating factors that can prevent restructuring of energy sector to create electricity market that can improve efficiency of power supply in Nigeria are analysed. Suggestions of steps or actions that should be taken into consideration before proposing solutions to some of the problems of power sector are also highlighted in this paper.

This paper implements an optimized solution to Over Current Relay Coordination (OCR) using a new metaheuristics algorithm called Smell Agent Optimization (SAO). We first formulate the relay coordination as a single objective multi-variable optimization problem. The main objective of the optimization is to optimize the time required for operation of the protective relays. We employed the IEEE standard 15-bus and IEEE standard 30-bus test networks to implement the OCR methods. Simulations were carried using Matlab R2019b and results were compared with Particle Swarm Optimization (PSO). Experimental analysis of results showed that both SAO and PSO algorithms are effective in solving the relay coordination problem. The SAO obtained a better solution when compared with the PSO, however, the PSO convergence was faster than SAO.

Дніпровський національний університет імені Олеся Гончара Розглянуто порівняно молодий вид онлайнової медійної діяльності-копірайтинг. Незважаючи на велику популярність та високу економічну ефективність, копірайтинг досі не системного осмислення. Між тим нагальним є науковий підхід, розробка належного понятійного апарату, вагомих методичних рекомендацій та узагальнень. У статті представлено результати дослідження, які спираються на існуючий науковий загал, практичний досвід копірайтерів, а також численні тексти, викладені в блогах авторитетних контентних студій та рекламних агентств. Сучасна медійна практика нерозривно пов'язана з контентотворенням та SEO-просуванням. Журналісти, PR-фахівці, пересічні власники онлайн-ресурсів щоденно стикаються з проблемою наповнення сайтів, їх оптимізацією під пошукові системи та просуванням. Українсько і російськомовні сегменти мережі Інтернет наповнені ресурсами, контент яких дублює один одного, створюючись за технологією копіпасту. Така ситуація суперечить чинному законодавству України, порушує етичні стандарти та аж ніяк не сприяє ефективному функціонуванню онлайнових текстів. Розробка комплексної науково-методологічної бази сприятиме усуненню негативної ситуації, що склалася та стане у нагоді копірайтерам-практикам. Галузь має вийти за межі суто практичної діяльності і набути свого наукового розуміння. У статті використано поділ процесу контентотворення на копірайтинг, рерайтинг, скан, переклад з інших мов, копіпаст, синонімайз, що є, на думку авторів, найоптимальнішим для сьогоднішнього стану цієї діяльності. З поданого переліку увагу закцентовано на копірайтингу як на найперспективнішій технології створення текстів для сайтів. Аналізуються усі наявні в УА та Рунеті види копірайтингу (іміджевий, SEO, LSІ-копірайтинг, SMM та написання текстів, які продають), а також виокремлюються головні вимоги до кожного з них. Ключові слова: копірайтинг; рерайтинг; контент; контентотворення; онлайнові ресурси. 1. Вступ Постановка проблеми. У світовій науці склалася дивна ситуація: глобальна Мережа прийшла у кожен дім, медіа, комерційні структури, офіційні установи, громадські організації. Видатні особистості, звичайні

Three-phase Induction motors are increasingly used in a variety of applications such as fans, milling machines, transportation, etc. In applications requiring precise speed control such as robotics, centrifugal pumps, mills and other high-performance applications, it is essential that speed is maintained constant at a desired fixed value.  Many speed control techniques exist in literature but this paper presents the design of a simple PI controller and its use to control the speed of a three-phase induction motor. A controller design that applies the Phase margin (PM) as the stability criterion is employed. The cross-over frequency and phase margin of the open loop gain of motor and controller are specified in order to develop a stable control system. The three-phase induction motor model is presented and modified for the purpose of control. A comparative analysis between the motor performance with and without the PI controller was performed. The unit step response of the speed cont...

Embedded systems find applications in fields such as defense, communications, industrial automation and many more. For majority of these applications, security is a vital issue. Cryptography plays an important role in providing data security. Until recently, symmetric key encryption schemes were used for a majority of these applications. Now however, asymmetric key encryption schemes such as Elliptic curve cryptography are gaining popularity as they require less computational power and memory and are still capable of providing equivalent security when compared to their counterparts. The authors of this paper have implemented scalar multiplication, the most time consuming operation in elliptic curve cryptography using binary non-adjacent form algorithm. The results of the software implementation have been presented in section-4. Methodology to improve the performance of the scalar multiplication by use of hardware accelerators has also been presented in this paper.

Modern mobile platforms like Android enable applications to read aggregate power usage on the phone. This information is considered harmless and reading it requires no user permission or notification. We show that by simply reading the phone's aggregate power consumption over a period of a few minutes an application can learn information about the user's location. Aggregate phone power consumption data is extremely noisy due to the multitude of components and applications that simultaneously consume power. Nevertheless, by using machine learning algorithms we are able to successfully infer the phone's location. We discuss several ways in which this privacy leak can be remedied.

Introduction The motivation of the paper is absolutely great. The authors mention that " sound is the primitive medium of unencrypted human communication (and side-product of many private activities) ". It is at least intriguing to think that nowadays much effort is made to improve security measures in digital communication (which is already understood to be considerably developed/secure) while little emphasis is placed on research exploring the security of something as rudimentary as sound, and in this case how to protect the auditory contents of private rooms (e.g. conference room). In fact, loudspeakers are commonly used in environments where acoustic privacy is essential, such as conference rooms. It is often assumed that the use of acoustic isolators can prevent private information leakage from loudspeakers. The authors of the paper explore a new acoustic eavesdropping method in which radio and Wi-Fi signals are utilized as a sensitive (non-acoustic) means for recovering possible audios generated inside acoustic-isolated rooms. The authors divide this method in two subparts: reflective vibrometry (when the eavesdropper generates radio signals into the victim's private room and collect/analyze the reflected signals) and emissive vibrometry (when the victim/eavesdropped has a loudspeaker and Wi-Fi on the same platform, and the eavesdropper can decode the loudspeaker audio by analyzing the Wi-Fi signals that are available).

Due to the amount of data that smartphone applications can potentially access, platforms enforce permission systems that allow users to regulate how applications access protected resources. If users are asked to make security decisions too frequently and in benign situations, they may become habituated and approve all future requests without regard for the consequences. If they are asked to make too few security decisions, they may become concerned that the platform is revealing too much sensitive information. To explore this tradeoff, we instrumented the Android platform to collect data regarding how often and under what circumstances smartphone applications are accessing protected resources regulated by permissions. We performed a 36-person field study to explore the notion of "contextual integrity," that is, how often are applications accessing protected resources when users are not expecting it? Based on our collection of 27 million data points and exit interviews with participants, we examine the situations in which users would like the ability to deny applications access to protected resources. We found out that at least 80% of our participants would have preferred to prevent at least one permission request, and overall, they thought that over a third of requests were invasive and desired a mechanism to block them.

Building security systems are commonly deployed to detect intrusion and burglary in home and business structures. Such systems can accurately detect door open/close events, but their high-cost of installation and maintenance makes them unsuitable for certain building monitoring applications, such as times of high/low entrance traffic, estimating building occupancy, etc. In this paper, we show that barometer sensors found in latest smartphones can directly detect the building door open/close events anywhere inside an insulated building. The sudden pressure change observed by barometers is sufficient to detect events even in presence of user mobility (e.g. climbing stairs). We study various characteristics of the pressure variation due to door events, and demonstrate that door open/close events can be recognized with an accuracy range of 99.34% -99.81% based on the data collected from 3 different buildings. Such a low-cost ubiquitous solution of door event detection enables many monitoring applications without any infrastructure integration, and it can also work as an augmentation to the existing expensive security systems.

Recognizing when eating activities take place is one of the key challenges in automated food intake monitoring. Despite progress over the years, most proposed approaches have been largely impractical for everyday usage, requiring multiple onbody sensors or specialized devices such as neck collars for swallow detection. In this paper, we describe the implementation and evaluation of an approach for inferring eating moments based on 3-axis accelerometry collected with a popular off-the-shelf smartwatch. Trained with data collected in a semi-controlled laboratory setting with 20 subjects, our system recognized eating moments in two free-living condition studies (7 participants, 1 day; 1 participant, 31 days), with Fscores of 76.1% (66.7% Precision, 88.8% Recall), and 71.3% (65.2% Precision, 78.6% Recall). This work represents a contribution towards the implementation of a practical, automated system for everyday food intake monitoring, with applicability in areas ranging from health research and food journaling.

This paper presents an approach for automatically detecting eating activities by measuring deformations in the ear canal walls due to mastication activity. These deformations are measured with three infrared proximity sensors encapsulated in an off-the-shelf earpiece. To evaluate our method, we conducted a user study in a lab setting where 20 participants were asked to perform eating and non-eating activities. A user dependent analysis demonstrated that eating could be detected with 95.3% accuracy. This result indicates that proximity sensing offers an alternative to acoustic and inertial sensing in eating detection while providing benefits in terms of privacy and robustness to noise.

Mobile devices are shrinking their form factors for portability, but user-mobile interaction is becoming increasingly challenging. In this paper, we propose a novel system called Okuli to meet this challenge. Okuli is a compact, low-cost system that can augment a mobile device and extend its interaction workspace to any nearby surface area. Okuli piggybacks on visible light communication modules, and uses a low-power LED and two light sensors to locate user's finger within the workspace. It is built on a light propagation/reflection model that achieves around one-centimeter location precision, with zero run-time training overhead. We have prototyped Okuli as an Android peripheral, with a 3D-printed shroud to host the LED and light sensors. Our experiments demonstrate Okuli's accuracy, stability, energy efficiency, as well as its potential in serving virtual keyboard and trackpad applications.

Recently a number of systems have been developed to implement and improve the visual communication over screen-camera links. In this paper we study an opposite problem: how to prevent unauthorized users from videotaping a video played on a screen, such as in a theater, while do not affect the viewing experience of legitimate audiences. We propose and develop a light-weight hardware-free system, called KALEIDO, that ensures these properties by taking advantage of the limited disparities between the screen-eye channel and the screen-camera channel. KALEIDO does not require any extra hardware and is purely based on re-encoding the original video frame into multiple frames used for displaying. We extensively test our system KALEIDO using a variety of smartphone cameras. Our experiments confirm that KALEIDO preserves the high-quality screen-eye channel while reducing the secondary screen-camera channel quality significantly.

We present LiSense, the first-of-its-kind system that enables both data communication and fine-grained, real-time human skeleton reconstruction using Visible Light Communication (VLC). LiSense uses shadows created by the human body from blocked light and reconstructs 3D human skeleton postures in real time. We overcome two key challenges to realize shadow-based human sensing. First, multiple lights on the ceiling lead to diminished and complex shadow patterns on the floor. We design light beacons enabled by VLC to separate light rays from different light sources and recover the shadow pattern cast by each individual light. Second, we design an efficient inference algorithm to reconstruct user postures using 2D shadow information with a limited resolution collected by photodiodes embedded in the floor. We build a 3 m × 3 m LiSense testbed using off-the-shelf LEDs and photodiodes. Experiments show that LiSense reconstructs the 3D user skeleton at 60 Hz in real time with 10 • mean angular error for five body joints.

Although GPS has become a standard component of smartphones, providing accurate navigation during the last portion of a trip remains an important but unsolved problem. Despite extensive research on localization, the limited resolution of a map imposes restrictions on the navigation engine in both indoor and outdoor environments. To bridge the gap between the end position obtained from legacy navigation services and the real destination, we propose FOLLOWME, a "last-mile" navigation system to enable plugand-play navigation in indoor and semi-outdoor environments. FOLLOWME exploits the ubiquitous, stable geomagnetic field and natural walking patterns to navigate the users to the same destination taken by an earlier traveler. Unlike existing localization and navigation systems, FOLLOWME is infrastructure-free, energyefficient and cost-saving. We implemented FOLLOWME on smartphones, and evaluated it in a four-story campus building with a testing area of 2000m 2 . Our experimental results with 5 users show that 95% of spatial errors during navigation were 2m or less with at least 50% energy savings over a benchmark system.