Kyong-Tak Cho

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Detecting how a vehicle is steered and then alarming drivers in real time is of utmost importance to the vehicle and the driver's safety, since fatal accidents are often caused by dan- gerous steering. Existing solutions for detecting dangerous maneuvers are implemented either in only high-end vehicles or on smartphones as mobile applications. However, most(More)
센서 네트워크에서 노드들의 한정된 전력량을 이유로 에너지 효율성은 MAC 프로토콜을 설계하는 데 있어서 중요한 요소이다. 센서 네트워크를 위한 MAC 프로토콜들은 전력 소모를 최소화하기 위해 낮은 듀티 사이클(Duty Cycle)을 사용한다. 그 중에서 RMAC [4]의 경우 Pioneer(PION) 프레임을 이용하여 한 주기 내에 여러 홉을 전송한다. 본 논문에서는 RMAC 과는 달리 한 주기 내에 전달될 수 있는 최대 홉 수 정보가 포함된 Explorer(EXP)를 이용하여 데이터 전송을 하는 HE-MAC 프로토콜을 제안한다. EXP 의 정보와 Ready-to-Receive(RTR) 상태를 이용하여 RMAC 에 비해 2 홉을(More)
As more software modules and external interfaces are getting added on vehicles, new attacks and vulnerabilities are emerging. Researchers have demonstrated how to compromise in-vehicle Electronic Control Units (ECUs) and control the vehicle maneuver. To counter these vulnerabilities, various types of defense mechanisms have been proposed, but they have not(More)
Contemporary vehicles are getting equipped with an increasing number of Electronic Control Units (ECUs) and wireless connectivities. Although these have enhanced vehicle safety and efficiency, they are accompanied with new vulnerabilities. In this paper, we unveil a new important vulnerability applicable to several in-vehicle networks including Control Area(More)
Several synchronous and asynchronous MAC protocols have been proposed for wireless sensor networks (WSNs). Among these, RMAC [2] exploits a control frame named Pioneer (PION) to set up the path and transmit a data packet through multiple hops in a single duty cycle. In this letter, we numerically analyze the average packet latency of RMAC in a probabilistic(More)
The duty cycle of a wireless sensor node is a key factor that determines the life time of a wireless sensor network. In general, sensor medium access control protocols reduce the duty cycle to achieve longer lifetime. However, we found out that their performance improvements substantially decrease under extremely low duty cycles (<0.1%). Our proposed W-MAC(More)
In wireless sensor MAC protocols, duty cycling has been exploited to put sensor nodes into sleeping state most of the time, thereby saving the limited battery efficiently. In this paper, we present a MAC protocol called Hop Extended MAC (HE-MAC) that enables a source node to transmit a data packet for multiple hops in a single duty cycle. It employs an EXP(More)
In this paper, we propose a new centralized routing protocol named WRP that aims at maximizing the network lifetime. In WRP, the sink node is assumed to be with more capabilities and basically collects each node’s estimated wakeup time. This enables the sink node to estimate the wakeup times of all sensor nodes even if some of them are multi-hops away from(More)
Femtocells are usually deployed in an indoor environment to provide in-building coverage enhancements. However, femtocells get to provide services for not only indoor users but also outdoor users in vicinity. Without the knowledge from the femtocell of whether the serviced users are located indoor or outdoor, the outdoor users are likely to experience low(More)