• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.3
• /
• pp.10-19
• /
• 2009

Wireless LAN systems have been widely implemented for supporting the wireless internet services especially in the hotspot areas such as hospitals, homes, conference rooms, and so on. Compared with wired LAN systems, wireless LAN systems have the advantages of the users' mobility support and low implementation and maintenance costs. IEEE 802.11 wireless LAN systems employ the backoff algorithm to avoid contentions among STAs when two or more STAs attempt to transmit their data frames simultaneously. The MAC efficiency can be improved if the CW values are adaptively changed according to the channel state of IEEE 802.11 wireless LANs. In this paper, a dynamic contention window control algorithm is proposed using the genetic algorithm to improve the MAC throughput of IEEE 802.11 wireless LANs.

• Journal of the Korea Safety Management & Science
• /
• v.17 no.1
• /
• pp.203-213
• /
• 2015

Recently, online grocery shopping has been increasing with the development of internet, mobile, and IT technology due to the proportion of consumers changes like increasing single households and double-income couples. Therefore, online sales from distributors with offline stores have also increased, and the offline retailers are facing their limits in dealing with store-based online channel they have carried out. Domestic offline retailers benchmarked overseas advanced retailers to solve this problem by reviewing about developing the online-only distribution center. However, much investment is needed in order to operate the distribution center with the new concept from abroad. In this study, we have reviewed the current online grocery market trend and the theory related to developing distribution system of the online mall. For offline retailers, we have reviewed the case which developed the distribution center applied to the nation's first online-only distribution center. The purpose of this study is reducing trial and error for local retailers in developing online-only distribution centers and suggesting ways to improve investment effect.

• Journal of Forest and Environmental Science
• /
• v.33 no.2
• /
• pp.130-135
• /
• 2017

In temperate monsoon regions, extensive shallow landslides triggered by heavy rainfall are recurrent phenomena in mountainous areas. 1,357 landslides over Jinbu area, Korea that totaled 127 km2 were identified from aerial photographs and field survey. We examined characteristics of rainfall-induced shallow landslides and casual factors affecting landslide distribution with respect to topographic and forest settings, and land use. Most landslides occurred in the study area were the results of a complex combination of precondition, preparatory factors and triggering factors. Cumulative rainfall and high intensity rainfall during short period of time made the study area very sensitive to landslides and played as catalysts to enable other factors including topographic and forest settings, and land use to act more effectively. In addition, some landslides at lower elevation involved channel incision or bank erosion influenced by land use changes such as deforestation and intensification of agriculture surrounding riparian forests or hillslopes. The results suggest that most of landslide were triggered by heavy rainstorms while topographic, forest settings, and land use affected landslide distribution occurred in the study area.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.13
• /
• pp.735-765
• /
• 2000

The paper aims to introduce and to discuss seafood import systems in terms of tariff and Non-Tariff Measurements which have been changed by the establishment of WTO. The paper can be used as materials for seafood trade policy making. The Non-Tariff Measurements for seafood import control in Japan are explored as follows; Import Quota, Import License, Pre-identification, Standard system, Customs Clearance Procedure, Import Port Nomination, Import Channel, Unification. The paper is composed of six chapters. Chapter 1 shows the current situation of seafood trade of major countries and background of the research. Chapter 2 deals with fisheries negotiations in the Uruguay Round, their impacts and major issues of tariffs and Non-Tariff Measurements in seafood trade. Chapter 3 analyzes seafood import of Japan, which is the core nation in the seafood trade of Northeast Asian Region, by item and the structure and characteristics of Japanese seafood import tariff including Non-Tariff Measurements. Chapter 4 and chapter 5 tackle seafood import management system of EU and USA respectively. Chapter 6 summarizes the issues of seafood import by focusing on Japan which is the biggest import market of Korean seafood.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.7
• /
• pp.279-291
• /
• 2020

This study aims to develop the concept of innovation models with the marketing channel construct approach, marketing innovation, product segmentation, and customer insight; as well as improvements to the theory of resource-based combined with the method of service-dominant logic. This study approach is based on quantitative descriptive conducted with three stages of testing scenarios. The first test is the mapping of the innovation model construct through testing the validity and reliability with the moderation of customer orientation variables. The second scenario examines the relationship of influence between the independent variables on the dependent variable of 29 hypothetical analysis equation modeling. The unit of analysis was conducted on 497 SMEs involved in the food and beverage sectors, with the criteria being SMEs must have a rating of 4-5 points on the Go-Food applications software. The results shown that: 1) the construct used to develop an innovative model both directly and via moderation is positive and significant; 2) Through a complicated relationship that involves all components of the variable, it outlines a positive and significant effect except for the path of analysis (μ5). The theoretical and managerial implications state that the service-dominant logic approach and resource-based view theory have extreme reliability and interrelations.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.23 no.3
• /
• pp.135-151
• /
• 1998

The demand of large capacity in coming cellular systems makes inevitable the deployment of small cells, rendering more frequent handoff occurrences of calls than in the conventional system. The key issue is then how effectively to reduce the chance of unsuccessful handoffs, since the handoff failure is less desirable than that of a new call attempt. In this study, we consider the control policies which give priority to handoff calls by limiting channel assignment for the originating new calls, and allow queueing the new calls which are rejected at their first attempts. On this system. we propose the problem of finding an optimal call control strategy which optimizes the objective function value, while satisfying the requirements on the handoff/new call blocking probabilities and the new call delay. The objective function takes the most general form to include such well-known performance measures as the weighted average carried traffic and the handoff call blocking probability. The problem is formulated into two different linear programming (LP) models. One is based on the direct employment of steady state equations, and the other uses the theory of semi-Markov decision process. Two LP formulations are competitive each other, having its own strength in the numbers of variables and constraints. Extensive experiments are also conducted to show which call control strategy is optimal under various system environments having different objective functions and traffic patterns.

• Smart Media Journal
• /
• v.2 no.3
• /
• pp.39-46
• /
• 2013

According to popularization of smart phones, we can easily see the QR code attached to products. Restaurants also provide customers with store information using QR code. Sixteen years have passed since QR code was developed. In Korea, QR code has been widely utilized in the field of marketing because of easiness of technique implementation and channel expansion to mobile. However, to recognize QR code, we should run the proper application and focus on it during loading time. To address this problem, this paper proposes the app to manage store information using NFC technology. The proposed app saves easily store information through the name card of a store and facilitates its management obtained by a smart phone.

• ETRI Journal
• /
• v.14 no.3
• /
• pp.1-15
• /
• 1992

Stand-slone 신호 중계 교환기인 SMX-1(Signalling Message eXchange No.1)은 통신망의 신경계인 공통선 신호망(Common Channel Signalling Network)의 하부 구조를 구성하는 시스팀이다. SMX-1에 총괄명 번역서비스를 수용하게 되면 통신망 사용자에게 통신망 내부의 구성 및 구성 요소의 변화에 구속되지 않고 지속적인 지능망 서비스를 제공할 수 있게 된다. 본 연구에서는 SMX-1의 설계 이념에 부합되도록 신호연결 제어부의 기능을 소프트웨어 및 하드웨어적으로 분산화하여 설계, 구현함으로써 SMX-1의 고신뢰성 및 신속성을 추구하였다. 소프트웨어적으로는 총괄명번역 서비스 제공을 위해 국제 전신 전화 자문 회의(CCITT)권고 Q.711-Q.714에서 정의하고 있는 신호연결 제어부(SCCP:Signalling Connection Control Part)의 기능을 관리 기능(SCMG : SCCP Management Part)과 루팅 제어 기능(SCRC : SCCP Routing Control Part)으로 분리하여 각각의 기능을 이중화하여 설계, 구현하였다. 하드웨어적으로는 관리 기능을 하나의 보드로 집중화하고 루팅 제어 기능을 여러개의 보드로 분산화하였다. 분산되어 있는 루팅 제어기능이 총괄명번역 서비스를 수행하기 위하여 사용하는 루팅 제어 데이터의 일치성을 유지하기 위하여, 관리 기능에 루팅 제어 데이터를 총괄적으로 관리하는 루팅 제어 데이터 관리 기능(RCDMFB : Routing Control Data Management Function Block)과 운용 관리 기능 (OMS : Operation and Management Subsystem)의 제원관리 지원기능을 구현하였다.

• Journal of Information Technology Applications and Management
• /
• v.27 no.5
• /
• pp.69-80
• /
• 2020

Recently, luxury brands are selling their products to consumers using their own direct online channels. In the online channel, marketing strategy through storytelling is needed because consumers do not have enough product experience. Therefore, luxury brands are actively utilizing social media and delivering stories includes their birth and growth. Unlike mass media, social media communicates with consumers more quickly and frequently and delivers the story of brand naturally. This study classifies luxury brands into four groups based on story recognition of luxury brands and self-esteem, and analyzes and materializes each group of the propensities of luxury brand consumption. It also tries to draw strategic implications for effective SNS advertising by analyzing narrative transportation on SNS advertising, interests in videos, and the interests in story based on these typified groups of luxury consumption. The result of the analysis shows that there is a difference in consumption propensity among consumers who were classified into four groups according to story cognition of luxury brands and self-esteem. There is also a difference in the response to narrative images through SNSs, such as narrative transportation, interests in videos, and interests in brand stories.

• Journal of IKEEE
• /
• v.7 no.2 s.13
• /
• pp.281-287
• /
• 2003

This paper proposed an improvement scheme for effective usage of radio-frequency management system(RFMS), which has been operated to facilitate national spectrum management and monitoring in Korea. Based on the wave propagation models, interference analysis algorithms, and sharing criteria recommended by ITU-R, we derived criteria for the automated selection of the channel interference analysis algorithms and sharing conditions adequate to the environment to be analysed. Then using the obtained criteria, computer and program has been made and shown to select the most appropriate propagation models, interference analysis algorithms, and sharing criteria from the ones provided in RFMS, with the illustrative example.