• 한국통신학회논문지
• /
• 제39C권1호
• /
• pp.106-113
• /
• 2014

This work proposes an analytic framework to estimate the capacity of the link in an M2M gateway that multiplexes a massive number of machine type communication devices. First, we specify the network architecture for M2M communications. Next, we summarize the characteristics of M2M traffic, from which we extract an area about the problem that has to be resolved in the dimensioning of the link capacity. After that we propose a new method to determine the capacity of the link in an M2M gateway. Via numerical experiment reflecting the realistic environment of M2M traffic, we illustrate the validity of the proposed model.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권2호
• /
• pp.687-708
• /
• 2017

The machine-to-machine (M2M) communication is featured by tremendous number of devices, small data transmission, and large uplink to downlink traffic ratio. The massive access requests generated by M2M devices would result in the current medium access control (MAC) protocol in LTE/LTE-A networks suffering from physical random access channel (PRACH) overload, high signaling overhead, and resource underutilization. As such, fairness should be carefully considered when M2M traffic coexists with human-to-human (H2H) traffic. To tackle these problems, we propose an adaptive Slotted ALOHA (S-ALOHA) and time division multiple access (TDMA) hybrid protocol. In particular, the proposed hybrid protocol divides the reserved uplink resource blocks (RBs) in a transmission cycle into the S-ALOHA part for M2M traffic with small-size packets and the TDMA part for H2H traffic with large-size packets. Adaptive resource allocation and access class barring (ACB) are exploited and optimized to maximize the channel utility with fairness constraint. Moreover, an upper performance bound for the proposed hybrid protocol is provided by performing the system equilibrium analysis. Simulation results demonstrate that, compared with pure S-ALOHA and pure TDMA protocol under a target fairness constraint of 0.9, our proposed hybrid protocol can improve the capacity by at least 9.44% when ${\lambda}_1:{\lambda}_2=1:1$and by at least 20.53% when ${\lambda}_1:{\lambda}_2=10:1$, where ${\lambda}_1,{\lambda}_2$ are traffic arrival rates of M2M and H2H traffic, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권10호
• /
• pp.3789-3809
• /
• 2015

In this paper, we deal with the problem of M2M gateways' network selection for different types of M2M traffic in heterogeneous wireless networks. Based on the difference in traffic's quality of service (QoS) requirements, the M2M traffic produced by various applications is mainly classified as two categories: flexible traffic and rigid traffic. Then, game theory is adopted to solve the problem of network-channel selection with the coexistence of flexible and rigid traffic, named as flexible network access (FNA). We prove the formulated discrete game is a potential game. The existence and feasibility of the Nash equilibrium (NE) of the proposed game are also analyzed. Then, an iterative algorithm based on optimal reaction criterion and a distributed algorithm with limited feedback based on learning automata are presented to obtain the NE of the proposed game. In simulations, the proposed iterative algorithm can achieve a near optimal sum utility of whole network with low complexity compared to the exhaustive search. In addition, the simulation results show that our proposed algorithms outperform existing methods in terms of sum utility and load balance.

• 한국도로학회논문집
• /
• 제15권6호
• /
• pp.33-39
• /
• 2013

PURPOSES : This research investigates traffic noise characteristics as change the transverse rumble strips shape from rectangular to cylinder at toll plaza of highway. METHODS : The traffic noise was investigated at two different places at toll plaza of highway. One is modified grooving, another is employed cylinder shape of TRS instead of rectangular shape of TRS. A measurement of traffic noise was conducted at same location and time period. The traffic volume information was gotten from office of highway office and vehicle speed was measured by speed measuring device. The traffic noise measurement was conducted from 13:00 to 23:00 and by pass-by method. Also, the traffic noise was measured behind noise barrier. Various distance from noise barrier(7.5m, 30m, 50m) and different heights(1.2m, 3m, and 5m) were parameter for measurement of traffic noise in this study. RESULTS : The class 1 vehicle was contributed from traffic volume which was increased 1,500. However, the distribution of traffic speed didn't change compare to previous investigated period. From this study, It was found that the external traffic noise was changed as function of geometric shape of TRS. The external noise from modified grooving was less than 1.2dB(A) of the current TRS. A difference of traffic noise was 20dB(A) before and after barrier. It came from a noise barrier effect as reduction of traffic noise. According to investigate a traffic noise distribution near barrier, there is similar noise characteristic as function of height at 7.5m distance from noise barrier. Also, There is no different traffic noise between 30m and 50m from source of the noise of sound barrier. CONCLUSIONS : Based on this traffic noise investigation result, there is a clear characteristic difference as changed TRS shape. The traffic noise was reduced by changed TRS shape. Specially, traffic noise was decreased although the traffic volume was increase for same investigation time and period. It is implied that cylinder type of TRS significantly reduces the traffic noise. The specification of various TRS will be studied in the future.

• 한국환경과학회지
• /
• 제26권4호
• /
• pp.467-481
• /
• 2017

This study sought to determine the changes in weather conditions in urban streets, along with conditions of traffic and roads in urban areas. The variations in weather conditions depending on traffic differed according to distance. First, the temperature difference measured by traffic results is as follows: T1 point $1.03^{\circ}C$, T2 point $1.04^{\circ}C$, T3 point $0.9^{\circ}C$, T4 point $1.01^{\circ}C$, and T5 point $0.31^{\circ}C$. The average difference between the measured temperatures by the point of measurement was $0.86^{\circ}C$. The changes in wind velocity according to traffic volume results of the measurements is T1 point 1.32 m/s, T2 point 0.80 m/s, T3 point 0.29 m/s, T4 point 0.04 m/s, and T5 point 0.09 m/s. The difference between the average wind speeds was 0.51 m/s and traffic jams caused substantial differences in distance. The relative humidity tended to be inversely proportional to temperature. The measurements results ares T1 point 2.29%, T2 point 2.67%, T3 point 2.47%, T4 point 2.16%, and T5 point 0.91% The difference between the average relative humidity was 7.3%. In case of independent sampling T test according to traffic volume, changes in wind velocity and temperature were directly proportional to the level of statistical significance(p<0.01). On the other hand, relative humidity tended to be inversely proportional; however, there was no statistical significance.

• 한국도로학회논문집
• /
• 제14권2호
• /
• pp.109-116
• /
• 2012

본 연구의 목적은 도시고속도로 합류부의 특성 및 실제 교통상황을 고려하여 각 차로별, 구간별로 영향권을 분석하는 것을 목적으로 하였다. 향후에는 본 연구결과를 바탕으로 차로제어시스템(Lane Control System, LCS) 등 운전자 정보제공서비스 및 첨단기술에 적용하여 효율적인 도로이용을 통한 원활한 운행상태유지가 가능할 것이다. 본 연구에서는 속도의 표준편차를 기준으로 고속도로 합류부의 난류현상을 분석한 기존연구를 기반으로, 난류현상 발생정도를 기준으로 한 세분화된 합류부 영향권을 도출하였다. 난류현상을 기준으로 도출한 합류부 영향권은 합류지점을 중심으로 합류지점과 유사한 교통류 특성을 보이는 구간을 합류의 직접영향권으로 도출하였으며, 도출된 결과는 상류부 300m에서 500m구간의 1, 2, 3차로, 합류지점에서 300m지점까지의 전차로 및 하류부 100m지점까지의 전차로, 하류부 100m에서 300m구간의 2, 3차로로 분석되었다.

• 한국환경보건학회지
• /
• 제24권2호
• /
• pp.110-117
• /
• 1998

This study was carried out to investigate the concentrations of TSP, Pb, Zn and Fe in ambient air adjacent to the heavy traffic road side in Seoul from October 1 to October 31, 1997. The results were as follows 1. The concentrations of TSP were 260 $\mu g/m^3$, 184 $\mu g/m^3$, 147 $\mu g/m^3$ in Chongro, Chungkechun and Kangnam-terminal, respectively. The concentration of TSP was correlated with the traffic volume of the sampling sites (r=0.77). 2. The concentrations of Pb were 638 ng/m$^3$, 335 ng/m$^3$, 233 ng/m$^3$ in Chungkechun, Kangnam-terminal and Chongro, respectively. The concentration of Pb was correlated with the Truck (over 1.4 ton) volume of the sampling sites (r=0.71). The Pb contents among these sites were significantly different (p < 0.05). 3. The concentrations of Zn were 535 ng/m$^3$, 461 ng/m$^3$, 439 ng/m$^3$ in Chongro, Kangnam-terminal and Chungkechun, respectively. The concentration of Zn was badly correlated with the traffic volume of the sampling sites (r=0.23). 4. The concentrations of Fe were 5.32 $\mu g/m^3$, 4.51 $\mu g/m^3$ and 3.18 $\mu g/m^3$ in Chongro, Kangnam-terminal and Chungkechun, respectively. The concentration of Fe was correlated with the traffic volume of the sampling sites (r=0.83). The Fe contents among these sites were significantly different (p < 0.05). 5. The concentrations of TSP, Pb, Zn, Fe investigated didn't exceed the Korean Ambient Air Quality Standards, but more researches in relation to these will be required in considering people working in these sites suffered from cough, asthma and chronic headache.

• 한국환경과학회지
• /
• 제18권4호
• /
• pp.389-400
• /
• 2009

In this research, we measured the number of lanes, distance, disposition of apartment that are affecting the road traffic noise to evaluate the current condition of G city's road traffic noise. We decide on a basis regarding an apartment price formation factor, and the apartment current price and the results that compared. To have a point scale, we set the maximum road traffic noise at a 8 lane road for 5 points, give 4 points for a 6 lane road, which has a $2.1{\sim}2.5\;dB(A)$ difference compared to a 8 lane road, give 3 points for a 4 lane road, which has a $5.2{\sim}5.5\;dB(A)$ difference compared to a 8 lane road, and set 2 points for a 2 lane road and lower. If we set the standard floor plan as horizontal and a living room facing the roadside, the horizontal and living room facing the opposite side of the road is 1 point because it differs by 14.1 dB(A), and the vertical is 3 points since the difference is 5.3 dB(A). If we make grades by the distance, making standard the fifth floor with little soundproof effect from apartment to road, we observe a measurement below 2.9 dB(A) at a distance of less than 10 m and 5 dB(A), decreased at a distance of 20 m. Therefore, 4 points were given for less than 10m, 3 points for $10{\sim}20\;m$, 2 points for more than 20 m as we can apply the effect of a decay distance of line sound source and the decrease in noise effects of more than 6 dB(A), 1 point for more than 40m, and 0 points for more that 80 m since it is negligible. 28 apartments got 0 points because there is no effect of road traffic noise from other apartments, and 50 apartments where only the road at one side effect them got $5{\sim}10$ points. 4 apartments (17-2, 6-3, 10-4, 3-3) received over 20 points. 15 cases showed a difference between developer price and resale price, and 11 cases (73%) among them showed the same trend (price increases with a low road traffic noise restriction factor point) with the point of road traffic noise restriction factor. 4 cases demonstrated the opposite trend, showing price increases with a high restriction factor point. Among the 4 cases, case numbers 2,6 and 9 appear to be more affected by the location factor (business district) than the road traffic noise restriction factor, and case number 1 appears to be affected by the building factor (openness and direction).

• 한국도로학회논문집
• /
• 제11권2호
• /
• pp.217-228
• /
• 2009

연속류도로 합류영향구간에서는 본선과 다른 교통특성을 가진 연결로교통류의 합류로 차로변경 및 가감속과 같은 차량간의 불규칙한 상호작용이 발생하여 교통류의 난류현상을 야기한다. 따라서, 난류현상은 운행상태를 고려하여 연속된 지점간의 불안정한 교통특성으로 판단하여야 한다. 본 연구에서는 합류영향구간에 차로-지점별 검지기를 설치하여 시공간적으로 연속된 교통자료를 구축하였으며, 지점간에 유의한 속도변화를 판단하는 기준으로 최소유의차(LSD) 통계값을 산정하여 난류현상을 분석하였다. 분석결과, 합류영향구간 난류현상은 운행상태에 따라 발생권역 및 심각도가 변화되는 것으로 나타났다. 이에 따라 난류현상에 의한 최대 합류영향권역은 교통량이 증가하는 혼잡전 운행상태에서 보여지며, 속도변화특성에 따라 상류 100m$\sim$하류 100m의 "감속구간"과 하류 100m$\sim$하류 400m의 "감속속도유지 및 가속구간"으로 구분할 수 있었다.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 춘계학술대회
• /
• pp.325-328
• /
• 2013

최근 국내 이동통신사들의 차세대 성장 동력으로 사물지능통신 (Machine to Machine, M2M)이 주목받고 있다. 따라서 그 쓰임새와 활용도가 각종 분야로 점점 넓어지고 있으며, 기존의 통신에 비해 사용되는 단말의 수가 점점 증가하게 되면서 사물마다 전송되는 정보들의 수도 증가하고 있다. 대량의 단말로부터 전송하는 각각의 데이터가 이동통신망을 이용하는데 있어 트래픽이 한계상황에 도달하게 된다면 M2M 통신의 서비스 처리를 원활하게 하지 못하는 상황이 발생 할 수 있다. 본 연구는 M2M 통신에서 사용하게 될 이동통신망이 한계점에 도달했을 때 M2M 서비스의 원활한 처리를 위한 방안을 제시한다. 이러한 방안은 데이터 트래픽이 한계점에 도달하게 된 이동통신망에서 우선적으로 처리해야 될 M2M 통신의 서비스 순위를 결정짓는데 사용 될 것이며, M2M 기술이 더욱 발전하게 되어 점차 소형화 되는 사물들이 많아짐에 따라, 폭증하게 될 이동통신망에서 M2M 서비스를 처리하는 것이 원활하도록 도움을 줄 것이다.