New Mathematical Model for Travel Route Recommendation Service

Intae Hwang(황인태),Heungseob Kim(김흥섭) 한국산업경영시스템학회 2017 한국산업경영시스템학회지 Vol.40 No.3

With the increased interest in the quality of life of modern people, the implementation of the five-day working week, the increase in traffic convenience, and the economic and social development, domestic and international travel is becoming commonplace. Furthermore, in the past, there were many cases of purchasing packaged goods of specialized travel agencies. However, as the development of the Internet improved the accessibility of information about the travel area, the tourist is changing the trend to plan the trip such as the choice of the destination. Web services have been introduced to recommend travel destinations and travel routes according to these needs of the customers. Therefore, after reviewing some of the most popular web services today, such as Stubby planner (http://www.stubbyplanner.com) and Earthtory (http://www.earthtory.com), they were supposed to be based on traditional Traveling Salesman Problems (TSPs), and the travel routes recommended by them included some practical limitations. That is, they were not considered important issues in the actual journey, such as the use of various transportation, travel expenses, the number of days, and lodging. Moreover, although to recommend travel destinations, there have been various studies such as using IoT (Internet of Things) technology and the analysis of cyberspatial Big Data on the web and SNS (Social Networking Service), there is little research to support travel routes considering the practical constraints. Therefore, this study proposes a new mathematical model for applying to travel route recommendation service, and it is verified by numerical experiments on travel to Jeju Island and trip to Europe including Germany, France and Czech Republic. It also expects to be able to provide more useful information to tourists in their travel plans through linkage with the services for recommending tourist attractions built in the Internet environment.

독립적인 MCS 레벨 선택 방식이 적용된 AMC-MIMO 결합 시스템의 성능 개선

김철성 ( Intae Hwang ),황인태 ( Kwang-wook Choi ),최광욱 ( Sang-jin Ryoo ),류상진 ( Kyung-hwan Lee ),이경환 ( Cheolwoo You ),유철우 ( Dae-ki Hong ),홍대기 ( Mingoo Kang ),강민구 ( Cheol-sung Kim ) 한국인터넷정보학회 2007 인터넷정보학회논문지 Vol.8 No.1

본 논문에서는 AMC-V-BLAST(Adaptive Modulation and Coding-Vertical-Bell-lab Layered Space-Time) 결합 시스템에 각 레이어 별로 공통적인 MCS(Modulation and Coding Scheme) 레벨을 적용한 경우와 독립적인 MCS레벨을 적용한 경우의 시스템 구조를 제시 후 성능을 관찰한다. 그리고 공통적인 MCS 레벨이 적용된 결합 시스템의 성능에 비하여 독립적인 MCS 레벨이 적용된 결합 시스템이 어느 정도의 전송률 향상이 있는가를 살펴본다. 실험결과, 독립적인 MCS 레벨이 적용된 경우가 레이어 별로 각 채널상태에 따라 최대한의 전송률을 얻기 위한 변조 및 코딩 방식이 선택되므로 공통 MCS 레벨을 적용한 경우에 비하여 전송률 성능이 우수함을 보였다. 특히, 약 7dB ~ 9dB SNR 구간에서 독립적인 MCS 레벨을 적용한 AMC-V-BLAST 결합 시스템의 경우가 공통적인 MCS 레벨을 적용한 경우에 비하여 약 700kbps의 전송률이 개선됨을 확인하였다. 또한, 수신다이버시티를 고려하며 MMSE 무효화 기법을 적용한 AMC-V-BLAST 결합 시스템의 경우 7dB ~ 9dB SNR 구간에 대하여 독립적인 MCS 레벨을 적용한 시스템과 공통적인 MCS 레벨을 선택한 시스템 간의 전송률 차이가 약 350kpbs 내외로 나타남을 확인할 수 있다. In this paper, we propose and observe a system that adopts Common-MCS (Modulation and Coding Scheme) level over all layer and Independent-MCS level for each layer in the combined AMC-V-BLAST (Adaptive Modulation and Coding-Vertical-Bell-lab Layered Space-Time) system. Also, comparing with the combined system using Common-MCS level, we observe throughput performance improvement in case of Independent-MCS level. As a result of simulation, Independent-MCS level case adapts modulation and coding scheme for maximum throughput to each channel condition in separate layer, resulting in improved throughput compared to Common-MCS level case. Especially, the results show that the combined AMC-V-BLAST system with Independent-MCS level achieves a gain of 700kbps in 7~9dB SNR (Signal-to-Noise Ratio) range against using Common-MCS level. In addition, the combined AMC-V-BLAST system using MMSEnulling method with receive diversity is verified that the difference of throughput between Independent MCS level system and common MCS level system in 7dB~9dB SNR is about 350kbps more or less.

NR 기반 다중 사용자 MIMO 시스템에서 하이브리드 프리코딩

문상미(Sangmi Moon),황인태(Intae Hwang) 한국통신학회 2019 한국통신학회 학술대회논문집 Vol.2019 No.6

IEEE 802.15.4a IR-UWB 패킷 분석기 설계 및 구현

임솔,이계주,김소연,황인태,김대진,Lim, Sol,Lee, Kye Joo,Kim, So Yeon,Hwang, Intae,Kim, Dae Jin 한국정보통신학회 2014 한국정보통신학회논문지 Vol.18 No.12

IR-UWB 기술은 실내 환경에 강인하고 투과성이 우수하며 저 전력 측위 시스템의 구현이 가능하다는 점에서 실내 측위 방식으로 표준화되어 개발되고 있다. 본 논문에서는 수십 cm급 IR-UWB 측위 시스템을 개발하는데 필요한 IEEE 802.15.4a를 기반으로 한 IR-UWB 패킷 분석기를 설계 및 구현하였다. 패킷 분석 시스템에서 스니퍼 디바이스는 IEEE 802.15.4a IR-UWB 네트워크를 감시하여 RF상의 패킷 프레임을 획득하여 패킷 분석기 PC 프로그램으로 전송한다. 패킷 분석기 PC 프로그램은 스니퍼로부터 받은 패킷 프레임을 IEEE 802.15.4a 표준에 맞게 분석하여 이를 사용자에게 보여주어 디바이스끼리 통신하는 정보를 분석할 수 있도록 한다. 개발된 패킷 분석기는 IEEE 802.15.4a MAC 프로토콜을 분석하는데 사용된다. 또한 일부 기능들을 수정보완하여 IEEE 802 시리즈의 다른 MAC 프로토콜을 분석하는데 사용할 수 있다. IR-UWB has been developed as a standard of indoor ranging technology, because it has robust and good transmission characteristics in indoor environments and it can be operated with low power. In this paper, a IR-UWB packet analyzer is designed and implemented based on IEEE 802.15.4a, which is useful in developing IR-UWB real time location system with resolution of a few ten centimeters. A sniffer device of the packet analyzer monitors IR-UWB wireless networks, captures MAC packet frames, and transmits packet frames to the packet analyzing computer. The packet analyzing program in a computer analyzes received MAC packet frames and displays parsed packet information for developing engineers. Developed packet analyzer is used to analyze IEEE 802.15.4a MAC protocol, and also it can be used in other IEEE 802 series MAC protocol by modifying some functions.

AMC와 MIMO 선택 기법이 결합된 통신 시스템의 설계 및 성능 분석

셰를리(Sherlie Portugal),황인태(Intae Hwang),이정환(Jeonghwan Lee),윤길상(Gilsang Yoon),조인식(Insik Cho),서창우(Changwoo Seo) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.3

본 논문은 AMC(Adaptive Modulation and Coding)와 MIMO(Multiple Input Multiple Output)를 결합하여 전송률 및 전송신뢰도 향상을 가져오는 통신 시스템을 구현한다. 또한 Precoding과 Antenna Subset Selection을 효율적으로 적용하고 MIMO 선택 기법을 결합하여, 최종적으로 AMC와 MIMO 선택 기법이 결합된 통신 시스템을 설계하고 성능을 분석한다. 모의 실험환경은 안테나 간 상관성이 존재하지 않는 주파수 비 선택적 레일리 페이딩 채널을 고려하였으며, 확산인자는 16을 적용하였다. 그 외의 여러 모의 실험 환경은 HSDPA(High Speed Downlink Packet Access) 표준에 근거하여 구성하도록 노력하였다. 본 논문에서 제안한 “AMC와 MIMO 선택 기법이 결합된 시스템”은 기존의 “AMC와 각 MIMO의 결합 시스템들”보다 높은 전송률을 보여주었으며, 열악한 채널 환경에서도 안정적인 전송률을 확보해 주었다. 제안된 시스템은 약 8㏈에서 최대 전송률을 나타내었으며, 제안된 시스템과 동일한 최대 전송률을 갖는 기존의 “AMC와 D-STTD 4×2 결합 시스템”과 비교하였을 때 약 6㏈ 정도 먼저 최대 전송률을 나타냈다. 또한 최대 전송률에 이르기 전까지 거의 모든 SNR(Signal to Noise Ratio) 구간에서 기존의 시스템보다 약 2배 정도 높은 전송률을 보였다. 구체적으로 SNR이 -6㏈인 지점에서 기존의 시스템은 약 2.5Mbps의 전송률을 나타냈으며, 제안된 시스템은 그 2배가 넘는 약 6.4Mbps의 전송률을 나타냈다. 또한 SNR이 2㏈인 지점에서는 각각 약 7.5Mbps와 15.3Mbps의 전송률을 나타내어 역시 2배에 가까운 차이가 나는 것을 확인할 수 있었다. 제안된 시스템은 AMC 기법을 사용하는 주 목적인 전송률의 향상에 크게 기여하였으며, 특히 평균 전송률의 향상에 효과적임을 확인하였다. This paper proposes a combination system of Adaptive Modulation and Coding (AMC) and Multiple Input Multiple Output (MIMO), which improves the throughput and has a better reliability. In addition, the system includes Precoding, Antenna Subset Selection and MIMO Mode Selection scheme. Finally, we make a performance analysis of the proposed system. The principal environmental parameters for the simulation experiment consist of a frequency non-selective rayleigh fading channel and a Spreading Factor (SF) of 16. Other parameters may be included in order to fulfill the requirements of the HSDPA Standard. The proposed system has a higher throughput and more reliability than the conventional system, which does not include MIMO Mode Selection scheme, Precoding or Antenna Subset Selection. According to the simulation results, the proposed system reaches the maximum throughput at 8㏈, presenting an improvement of 6㏈ and twice higher throughput, respect to the conventional system. Specifically, at the point of -6㏈, the conventional system reaches 2.5Mbps, while the proposed system reaches 6.4Mbps at the same SNR. Also, at the point of 2㏈, each system reaches 7.5Mbps (conventional system) and 15.3Mbps (proposed system), with near twice the difference. According to the results exposed above, we can conclude that the system proposed in this paper has, as the greatest contribution, the improvement of the throughput, especially, the average throughput.

154㎸ 초전도케이블 제주 금악-한림 계통 적용영향 검토

이승렬(Seung Ryul Lee),황인태(Intae Hwang),윤재영(Jaeyoung Yoon),박진우(Jin-woo Park),강연욱(Yeon-Woog Kang) 대한전기학회 2015 대한전기학회 학술대회 논문집 Vol.2015 No.4

±80kV DC 초전도케이블 제주계통 기본영향 검토

이승렬(Seungryul Lee),황인태(Intae Hwang),윤재영(Jaeyoung Yoon),양병모(Byeongmo Yang) 대한전기학회 2013 대한전기학회 학술대회 논문집 Vol.2013 No.7

조류발전사업 환경영향평가

박성우(Sungwoo Park),황인태(Intae Hwang) 한국신재생에너지학회 2017 한국신재생에너지학회 학술대회논문집 Vol.2017 No.9

초전도한류기의 실계통 적용을 위한 적응형 보호알고리즘

이승렬(Seungryul Lee),황인태(Intae Hwang),윤재영(Jaeyoung Yoon),양병모(Byongmo Yang) 대한전기학회 2012 대한전기학회 학술대회 논문집 Vol.2012 No.5

This paper proposes a new adaptive protection algorithm to apply the SFCL to a real power system. The proposed algorithm considers the impedance change of the power system with the SFCL in a fault condition.

초등영어 학습자와 교사가 인식하는 불안감

박선호(Park, Seon-Ho),황인태(Hwang, Intae) 한국외국어교육학회 2012 Foreign languages education Vol.19 No.3

This study aims at investigating anxieties perceived by elementary school students and Korean English teachers both in and outside the English c1asses and suggesting the ways to reduce their anxieties. Seven students and five English teachers were carefully selected with proper references in terms of their profiles including gender and academic levels, and teaching careers from three areas of Seoul, Gyeonggido, and Inchon. They were interviewed with semi-structured interview schedules to gain the information about their anxieties. Data from teacher’s observation were also used for analyzing and interpreting their types and characteristics of anxieties. Elementary school students and English teachers were found to perceive a variety of anxieties. English-related anxieties were turned out to have critical impacts on the students’ motivations and achievements in English language learning. They also tended to cause low levels of satisfaction and efficiency to English teachers in their teaching profession. The findings implied the necessities of reducing students’ and teachers’ anxieties from learning and teaching English. Based on the findings from the study, some practical suggestions are made for more successful English education in elementary schools.