오프라인과 온라인 채널상의 기존제품과 신제품의 판매 성과: 경험재에 대한 시계열 분석을 중심으로

김지연 ( Jeeyeon Kim ),김민경 ( Mingyung Kim ),최정혜 ( Jeonghye Choi ) 한국지식경영학회 2015 지식경영연구 Vol.16 No.4

We examine offline and online channel sales of experience goods, and compare and contrast the sales patterns of existing products and new products between channels. To this end, we obtain the channel-specific time-series sales data from the leading company selling beauty products, both onine and online. By applying the Vector Autoregressive Model, we empirically find out how the relationship between existing products and new products changes between the shopping channels. Our empirical findings are as follows. First, the sales effects from existing products to new products are significantly positive at both online and online channels, and this positive effect is greater in the online channel than in the online channel. Second, the influence of new products on existing products is more positive in the online channel than in the online channel. Third, the impact of existing products sales on new products sales is greater than that of new products on existing products. Lastly, the inertia effect, the effect within the same shopping channel and the same selling product, is significantly positive in the offline channel but not in the online channel, and this asymmetric inertia effect emerges as we focus on experience goods. Moreover, the impulse response function analysis provides the three important implications. First, companies should pay attention to the same channel but different types of products. Second, the online channel is more vulnerable to market shock than the online channel. Third, new products sales vary by existing products sales to the greater extent, compared to the opposite relationship. We believe our study contributes theoretically and practically to the fields of marketing and knowledge management.

On MIMO Channel Modeling for the Mobile Wireless Systems

Rachna Mahey,Dr. Jyoteesh Malhotra 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.5

Developments in the area of wireless communications have constantly aimed at providing higher data rates even under complex environments using multiple-input multiple-output (MIMO) systems. Hence it generates a huge demand to investigate and understand the MIMO channel models for mobile wireless systems. Channel models describe the communication environments and are necessary in developing efficient wireless communication networks. This paper surveys the different channel models used to characterize the wireless systems. Generally, the channel models are classified as Physical models and Analytical models. These models are analyzed here along with the discussion of popular examples from both model types. The MIMO channel models employed in the current standardization activities to evaluate the MIMO system are also reviewed. Finally, some issues regarding these channel models are highlighted.

제품특성에 따른 물적유통경로선택 분석

박민영,김찬성,박동주,Parichart Pattanamekar,김은미 대한교통학회 2010 大韓交通學會誌 Vol.28 No.1

The study developed physical distribution channel choice models reflecting decision making of the firms and studied how choice decision factors influence selection of distribution channel. The distribution channel survey data in Korea was used to do empirical study. As a choice set, distribution channels were classified into two main choice channels: direct and indirect channels. In addition, indirect channels were classified into other three channels according to the type of intermediate point: distribution center, wholesale store, and agency. This study developed choice models by applying both binary and multinomial logit model with various set of factors. The results showed that the developed logit models seemingly reflect distribution channel choice behaviors. The hypothesis tests on how each factor influences choice of distribution channel were performed and discussed as well. 최근 국내에서는 민간 분야뿐만 아니라 공공물류에의 활용을 위해 좀 더 신뢰성 있고 개선된 화물수요추정방법에 대한 관심이 높아지고 있다. 현재 화물수요분석의 기초자료로 활용되고 있는 지역 간 화물기종점통행량(OD)자료는 각 화물의 생산지와 소비지 사이의 이동과 전환관계가 복잡함에도 불구하고 출발지와 목적지 사이의 환적시설이나 물류시설을 노드로 구분하지 않고 각 존의 물동량에 포함시킴으로써 화물의 정확한 이동이나 전환관계를 파악하지 못하게 하는 한계점을 지니고 있다. 본 연구의 목적은 이러한 인식하에 개별의사결정자인 기업에 의해 이동되는 화물의 물적인 흐름을 분석하기 위한 물적 유통경로 선택모형을 개발하는 것이다. 이는 개별회사의 의사결정에 있어 매우 거시적인 개념이며, 개별의사결정자인 기업이 유통경로를 선택할 때 어떠한 요소를 고려하는 지를 살펴보고자 하였다. 본 연구에서는 2007 화물유통경로조사의 내수화물자료를 중심으로 기초통계분석을 수행하고 물적 유통경로 선택모형을 구축하였다. 또한 구축된 모형이 합리적인지 평가하기 위해 최종모형에 대해 유통경로선택이론을 기초로 가설검증을 수행하고 적중률을 산출하였다. 선정된 최종모형의 가설 검증결과, 제조업체는 유통경로선택시 도착지점의 시장특성, 업종 및 품목특성, 경로특성, 기업의 크기 및 경제력 등을 중요하게 고려하는 것으로 나타났다.

고속 시변 채널 OFDM을 위한 저복잡도 LS 채널 예측의 성능 개선

임동민 대한전자공학회 2012 電子工學會論文誌-TC (Telecommunications) Vol.49 No.8

본 논문에서는 고속 시변 채널 OFDM을 위한 저복잡도 LS(Least Squares) 채널 예측의 성능 개선 방안을 제안한다. 저복잡도 LS 채널 예측을 위해 사용하는 CE-BEM(Complex Exponential-Basis Expansion Model) 채널 모델의 경우 채널 모델 자체의 문제점으로 인하여 채널 예측 성능 저하가 발생한다. 본 논문에서는 우선 시간 영역 윈도우를 이용하여 데이터 심볼에 의한 ICI(Interchannel Interference)의 영향을 제거한다. LS 채널 예측 결과에서 샘플을 취하여 윈도우의 영향을 제거한 후 특성이 채널 변화의 표현에 적합한 DPSS(Discrete Prolate Spheroidal Sequences)를 기저함수(basis function)로 하는 보간(interpolation) 방식으로 채널 응답을 복원하여 CE-BEM의 문제점을 해결한다. 컴퓨터 모의실험을 통한 성능 확인 결과 제안된 채널 예측 방식은 기존의 방식과 비교하여 특히 고속 시변 채널에서 우수한 성능 개선 효과를 보여주며, 선택된 기저함수의 형태뿐만 아니라 기저함수의 개수의 설정이 성능을 크게 좌우하는 또 다른 요소임을 확인하였다. In this paper, we propose a method for improving the performance of low complexity LS channel estimation for OFDM in fast time varying channels. The CE-BEM channel model used for the low complexity LS channel estimation has a problem on its own and deteriorates channel estimation performance. In this paper, we first use time domain windowing in order to remove the effect of ICI caused by data symbols. Then samples are taken from the results of the LS channel estimation and the effects of the windowing are removed from them. For resolving the defect of CE-BEM, the channel responses are recovered by interpolating the resultant samples with DPSS employed as basis functions the characteristics of which is well matched to the time variation of the channel. Computer simulations show that the proposed channel estimation method gives rise to performance improvement over conventional methods especially when channel variation is very fast and confirm that not only which type of functions is selected for the basis but how many functions are used for the basis is another key factor to performance improvement.

대응분석을 이용한 은행 채널전략 수립 연구 : 고객의 은행채널 선택요인을 바탕으로

박운학,박영배 한국산업정보학회 2023 한국산업정보학회논문지 Vol.28 No.6

For the efficient establishment of a channel strategy for banks, this study aims to propose a channel model by classifying channels into types, and carrying out a correspondence analysis per type. A survey of bankers was conducted to visualize categorical data and create a positioning map. As a result, first, 12 banking channels were classified into 4 types based on business processing subjects and places, which were then, further grouped into the categories of full-banking and self-banking. Second, a correspondence analysis according to the classified types was carried out, and it was found that the branch-type is suitable for product description and customer management, while the banking-type is suitable for efficient business processing without time and space constraints. Furthermore, the analysis also showed that the machine-type and banking-type are inappropriate for customer management, and the mobility-type demonstrates low operational effectiveness due to a lack of awareness. The aforementioned findings suggest the need for a hybrid convergence channel that reflects the characteristics of banking tasks and fills in the gaps between the different channels. Third, a channel model was derived by adding a common area to the 2x2 model consisting of the business processing subjects and places. Therefore, this study is meaningful in that it examines the diversification of channels and factors in the division of roles by channel type based on customers' banking channel selection factors, and presents basic research findings for future channel strategy establishment and efficient channel operation. 본 연구의 목적은 은행의 효율적인 채널전략 수립을 위해 채널을 유형별로 분류하고, 분류된 유형에 따라 대응분석을 실시하여 채널모형을 제안하는 것이다. 이를 위해 은행원 대상 설문조사를 실시하여 범주형 자료를 시각화하고 포지셔닝 맵을 작성하였다. 그 결과 첫째, 12개 은행채널을 업무처리 주체와 장소를 기준으로 4개 유형으로 분류하고, 이를 다시 풀뱅킹과 셀프뱅킹으로 그룹화 하였다. 둘째, 분류된 유형에 따라 대응분석을 실시하여 점포형은 상품설명과 고객관리에 적합하고, 뱅킹형은 시·공간 제약 없이 효율적인 업무처리에 적합하며, 기기형과 뱅킹형은 고객관리에 부적합하고, 이동형은 인식부족으로 운영효과가 낮은 상태라는 결과를 도출하였다. 이는 은행업무의 특성을 반영하고 채널간 부족한 부분을 보완하는 하이브리드형 융합채널이 필요함을 의미한다. 셋째, 업무처리주체와 장소로 구성된 2x2모형위에 공통분면이 추가된 채널모형을 도출하였다. 따라서 본 연구는 고객의 은행채널 선택요인을 바탕으로 채널 다각화와 채널유형 별 역할분담 요소를 고찰함에 기여하고, 미래채널 전략수립과 효율적인 채널운영을 위한 기초연구 결과를 제시하였다는 점에서 연구의 의의를 가진다.

Modeling of Doppler Power Spectrum for Underwater Acoustic Channels

Do Viet Ha,Nguyen Van Duc,Nguyen Quoc Khuong 한국통신학회 2017 Journal of communications and networks Vol.19 No.3

In this paper, we propose a closed-form expression of Doppler power spectrum model for underwater acoustic (UWA) channels. Using the geometry model for shallow UWA channels, we analyze the theoretical background of Doppler effects generated by the transmitter/receiver (Tx/Rx) movement, or by the motion of sea-surface. As a result, the Doppler power spectrum can be modeled as a summation of the Spike-shape and the Gaussian-shape. The Spike-shape presents the Doppler component from the Tx/Rx movement, while the Gaussian-shape presents the Doppler component from the sea-surface motion. The proposed model is validated through curve fitting with the Doppler power spectrum measurement results of a real shallow UWA channel in Halong bay, Vietnam. The optimal parameters of the proposed model are derived from the measurement results by applying an optimization algorithm called the Lp-norm method. The curve fitting results show that our proposed model matches well with the measurements. Therefore, the proposed Doppler model can accurately describe the Doppler effects for shallow UWA channels. The proposed model can be used to design UWA channel simulators for the performance evaluation of UWA communication systems.

다중 경로 페이딩 채널 모델들의 특성 분석

元寅載,朴帝賢,金正國 明知大學校 産業技術硏究所 2005 産業技術硏究所論文集 Vol.24 No.-

Rayleigh signal fading phenomena due to multipath propagation in wireless communication can be simulated using the sum-of-sinusoids channel model. Jakes' fading channel model and Clarke's fading channel model are very simple simulators based on the sum-of-sinusoids and has been widely used. However, It has some short-comings. Its time correlation properties based on the simulated waveform do not correspond to the statistical ones. In this paper, the difference between statistical and time properties of Jakes' fading channel model and Clarke's fading channel model are examined.

IEEE 802.11p MAC 기반 차량 네트워크에서의 분산된 브로드캐스팅 모델링

정대인(Daein Jeong) 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.11(네트워크)

본 논문은 차량 네트워크에 적용되는 IEEE 802.11p MAC 프로토콜에서의 브로드캐스팅 동작을 모델링하였다. 도로상의 안전 서비스 구현에 필요한 beacon 메시지는 브로드캐스팅 방식으로 교환되는데 최적의 안전 서비스 구축을 위해 브로드캐스팅 동작의 해석적 모델링이 필요하다. 모델링에 반영된 IEEE 802.11p 고유의 특성은, CCH(Control Channel)와 SCH(Service Channel) 간의 채널 스위칭 동작과 이로 인해 beacon 메시지를 교환하는 CCH 구간이 시간적 제한을 갖는다는 점, 그리고 재전송이 없다는 점이다. 이러한 고유 특성이 반영된 모델링 설계에서 본 논문은 beacon 메시지의 발생 패턴에 대한 제한을 두지 않았다. 즉, CCH 구간 내 분산된 발생 및 브로드캐스팅을 모델링하였다. 시뮬레이션 결과와의 비교를 통해 본 논문에서 제안한 모델링의 정확성을 확인하였다. 또한, beacon 메시지 발생 및 브로드캐스팅을 분산시킴으로써 전달률, 전송 지연 및 지연의 변동성 등 모든 성능지표가 개선되는 것을 확인하였다. In this paper, we propose a modeling of the broadcasting in the IEEE 802.11p MAC protocol for the VANET(Vehicular Ad hoc Networks). Due to the fact that the beacon message which is needed for the safety services is shared via broadcasting, the analytical modeling of the broadcasting is crucial for the optimum design of the services. Two characteristics specific to the IEEE 802.11p are reflected in the modeling; the time limited CCH interval caused by the channel switching between the CCH and SCH, and no retransmission of the broadcasted messages. In the proposal, we assumed no restriction on the moment of generation of the beacon messages. We allow the messages to be generated and broadcasted within the whole CCH interval. Simulation results prove the accuracy of the proposed modeling. Noticeable improvements are also observed in terms of the performance indices such as the successful delivery ratio, transmission delay, and the variation of the delay.

무선 센서 네트워크 채널 분석

정경권(Kyung Kwon Jung),최우승(Woo-Seung Choi) 한국컴퓨터정보학회 2008 韓國컴퓨터情報學會論文誌 Vol.13 No.5

무선 센서 네트워크의 응용범위가 늘어남에 따라 정확한 무선 채널의 정보를 필요로 한다. 실내 또는 실외의 무선 센서 네트워크의 경우 페이딩에 의한 다중 경로 전파가 문제를 일으키고 있다. 본 논문에서는 실내 2.4 ㎓ 채널에 대한 log-normal path loss 모델링을 살펴본다. 송신기와 수신기 사이의 거리를 1에서 30 m까지 변화시키면서 수신 신호 강도 변화를 측정하고, 채널의 감쇄지수와 표준편차를 계산하였다. 계산한 모델의 패킷 수신율을 이용하여 무선 센서 채널을 연결 영역과 차단 영역으로 정의하고, 시뮬레이션과 실험 결과를 통해서 무선 채널의 특징을 비교하였다. 실험결과 실내에서의 연결 영역은 24 m, 실외에서의 연결 영역은 14 m로 측정되었다. In proportion as the growth of the wireless sensor network applications, we need for more accuracy wireless channel information. In the case of indoor or outdoor wireless sensor networks, multipath propagation causes severe problems in terms of fading. Therefore, a path-loss model for multipath environment is required to optimize communication systems. This paper deals with log-normal path loss modeling of the indoor 2.4 ㎓ channel. We measured variation of the received signal strength between the sender and receiver of which separation was increased from 1 to 30 m. The path-loss exponent and the standard deviation of wireless channel were determined by fitting of the measured data. By using the PRR(Packet Reception Rate) of this model. Wireless sensor channel is defined CR (Connect Region), DR(Disconnected Region). In order to verify the characteristics of wireless channel, we performed simulations and experiments. We demonstrated that connection ranges are 24 m in indoor, and 14 m in outdoor.

Simulation of Pesticide Fate and Transport in Drainage Channels

Chung, Sang-Ok,Park, Ki-Jung,Christen, E.W. The Korean Society of Agricultural Engineers 2005 한국농공학회논문집 Vol.47 No.7

Contamination in the drainage channels and creeks with pesticides used in agriculture is of a major concern in many countries. In this study the stream pesticide model RIVWQ (chemical transport model for riverine environments) was assessed for its applicability in simulating pesticide fate in drainage channels. The model was successfully calibrated against field data collected on flows and pesticide concentrations for a drainage channel from a small catchment in the Murrumbidgee Irrigation Area of southwestern New South Wales. The effects of different pesticide loading scenarios from farm fields on channel water quality were analysed by the calibrated model. The model simulated the flow rates and the pesticide concentrations in the drainage channel well. The results of the model simulation suggest that the RIVWQ model can be effectively used for predicting pesticide fate in the drainage channels and exposure assessment of pesticide in the agricultural environment.