• Smart Media Journal
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• v.13 no.1
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• pp.45-51
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• 2024

Long Range Wide Area Network (LoRaWAN) is a widely adopted Internet of Things (IoT) protocol due to its high range and lower energy consumption. LoRaWAN utilizes Adaptive Data Rate (ADR) for efficient resource (e.g., spreading factor and transmission power) management. The ADR manages these two resource parameters on the network server side and end device side. This paper focuses on analyzing the ADR and Gaussian ADR performance of LoRaWAN. We have performed NS3 simulation under a static scenario by varying the antenna height. The simulation results showed that antenna height has a significant impact on the packet delivery ratio. Higher antenna height (e.g., 50 m) has shown an improved packet success ratio when compared with lower antenna height (e.g., 10 m) in static and mobility scenarios. Based on the results, it is suggested to use the antenna at higher allevation for successful packet delivery.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1368-1373
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• 2015

Recently, There is increasing interest in the IoT(Internet of Thing) as intelligent information service that enables communication between people and things based on internet. In particular the demand for indoor location-based services with the development of smart devices is rapidly increasing. Using the RSSI signal that is provide to the BLE(Bluetooth Low Energy) for Indoor location information measurement calculates distance information between beacon and mobile terminal. However, simply using the RSSI signal to the distance measurement has a difficult to get the indoor location information due to the influence of the signal interference and the weather. In this paper, by performing an operation for obtaining a reliable distance information from the signal information of iBeacon we propose a system for providing reliable indoor location.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.5
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• pp.155-162
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• 2014

We proposed a 2 level tree based cluster based routing protocol for mobile ad hoc networks. it is our crucial goal to establish improved clustering's structure in order to extend average node life-time and elevate the average packet delivery ratio. Because of insufficient wireless resources and energy, the method to form and manage clusters is useful for increasing network stability. but cluster-head fulfills roles as a host and a router in clustering protocol of Ad hoc networks environment. Therefore energy exhaustion of cluster-head causes communication interruption phenomenon. Effective management of cluster-head is key-point which determines the entire network performance. The scheme focuses on improving the performance the life time of the network and throughput through the management of cluster-heads and its neighbor nodes. In simulation, we demonstrated that it would obtain averagely better 17% performance than LS2RP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.66-72
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• 2016

An LED lighting control system was developed to combine information technology and LED lights for efficient management and energy savings. The system can monitor and control the status of an LED luminaire using Bluetooth wireless communication, sensor technology, and smart phones. An LED lighting control circuit was designed using a temperature sensor, illumination sensor, and Bluetooth module with a fuzzy constant-current control circuit. We extended the lifetime and prevented damage to the LED by optimizing the supply current of the LED luminaire based on the heat-generation temperature of $70^{\circ}C$ of an LED heat sink. We also automatically adjusted the ON/OFF time depending on the ambient illumination of the LED luminaire. By allowing easy control of the LED luminaires on a smartphone, we improved the efficiency and achieved energy savings. The control system was validated through experiments for normal operation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2347-2356
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• 2017

Raspberry Pi has been widely used for a hardware platform to develop the Internet of Things (IoT) applications. The basic task of diverse IoT devices is to obtain their status or environmental information by using various sensors and to send them to a gateway or a remote server. For the purpose, one of application layer protocols for IoT, MQTT is widely used. IoT devices are often powered by batteries and they are required to operate for a long time without replacing or recharging their batteries. Thus, energy efficiency is one of the most critical problems for obtaining and sending sensor data. To develop energy-efficient IoT applications, the information about power consumption characteristics of the applications is necessary. However, there has been little study to analyze power consumption of IoT communication on IoT devices. This paper presents a study to measure and analyze the power consumption of sending/receiving data under various conditions via the MQTT protocol on Raspberry Pi.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.153-158
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• 2017

Rendezvous point is used to gather the data from sensor nodes and send to sink node efficiently in selected area. It incurs a unbalanced energy consumption nearby the rendezvous point which can shorten the network life time shortly. Thus, it is very important to select the rendezvous point effectively among all sensors in order to not drain the battery of a sensor node in construction sites. In this paper, we propose a rendezvous point replacement mechanism which considers remaining energy of nodes to prolong the network lifetime. Also, for shortening the distance of drone at the same time, it increases the probability of the near-by drone node becoming rendezvous point. The simulation results show that the proposed scheme can significantly improve the network lifetime and the flight distance compared with the existing LEACH, L-LEACH algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.19-25
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• 2011

With the issue of a Green IT Technology, studies on a environment-friendly luminous source that can reduce Carbon discharge and increase energy efficiency are actively progressed all over the world. Especially, with the problems of high oil price and environmental pollution, LED has made a great attention as a new luminous source that can replace the existing incandescent bulbs and fluorescent lights. In this paper, the proposed streetlight system becomes more intellectual by combining the low power consuming, high efficient, and high luminous LED module with a complex sensor module with temperature, humidity, illumination and motion sensors. Then, we design and implement the Ad-Hoc based LED-IT-Sensor integrated streetlight system that can maximize the energy savings efficiently with central monitoring system and selective remote dimming control by connecting them to the wireless ubiquitous sensor network(USN) using a Zigbee module.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1949-1954
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• 2016

Smart grid technology can be called grid techniques to improve the efficiency of the electric power by exchanging bidirectional information of electric power with real-time between electric power suppliers and consumers. Recently, the solar power generation system is being applied actively. However the solar power system has several problems leading to reduce overall electricity generation, because the difficult of the diagnosis and the solar power system failure such as PV(PhotoVoltaics) and inverter. In order to build an efficient smart grid, a stable electric power energy requirements capture and management and early fault detection is essentially required in solar power generation system. In this paper, it is designed to monitor the operating status of the solar power monitoring system from a remote location through a RS-485 or TCP/IP communication module to monitoring the output of solar power energy and abnormal phenomenon, to developing the measurement module and to transfer measured data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1082-1087
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• 2021

In MANET(mobile ad hoc network), Mobility models vary according to the application-specific goals. The most widely used Random WayPoint Mobility Model(RWPMM) is advantageous because it is simple and easy to implement, but the random characteristic of nodes' movement is not enough to express the mobile characteristics of the entire sensor nodes' movements. The random mobility model is insufficient to express the inherent movement characteristics of the entire sensor nodes' movements. In the proposed Stochastic mobility model, To express the overall nodes movement characteristics of the network, the moving nodes are treated as random variables having a specific probability distribution characteristic. The proposed Stochastic mobility model is more stable and energy-efficient than the existing random mobility model applies to the routing protocol to ensure improved performances in terms of energy efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.291-298
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• 2023

SRAM-based in-memory computing is one of the technologies to solve the bottleneck of von Neumann architecture. In order to achieve SRAM-based in-memory computing, it is essential to design efficient SRAM bit-cell. In this paper, we propose a low-power differential sensing 8+T SRAM bit-cell which reduces power consumption and improves circuit performance. The proposed 8+T SRAM bit-cell is applied to ripple carry adder which performs SRAM read and bitwise operations simultaneously and executes each logic operation in parallel. Compared to the previous work, the designed 8+T SRAM-based ripple carry adder is reduced power consumption by 11.53%, but increased propagation delay time by 6.36%. Also, this adder is reduced power-delay-product (PDP) by 5.90% and increased energy-delay- product (EDP) by 0.08%. The proposed circuit was designed using TSMC 65nm CMOS process, and its feasibility was verified through SPECTRE simulation.