• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.34-45
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• 2008

Broadcast encryption schemes are applied to transmit digital informations of multimedia, software, Pay-TV etc. in public network. User acquires message or session key to use key that broadcaster transmits, broadcaster need process that generation and distribution key in these process. Also, user secession new when join efficient key renewal need. In this paper, introduce about efficient key generation and distribution, key renewal method. The temporary conference environment base structure against an each mobile device wild gap. Without the transmission possible, it follows infrequent location change and with the quality where the key information change flow. Thus, in this paper, in order to apply to the embedded computing environment and the key generation and the efficient key renewal are done when the mobile device is used of the specify space it proposes.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.103-113
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• 2009

Motorola which had developed and commercialized wireless telephone and mobile phone for the first time in the world made a decision on the separation of the mobile unit from the Motorola due to the continuous bad performance turn. In addition, the Korean company named Raincom which had developed and commercialized MP3 player have been disappeared since Raincom failed to compete with iPod of Apples. What is the main cause the companies that have been top of the world level weed out of IT product market? For less product life cycle and globalization of market, the company's competitiveness tends to be determined based on company's creative capability, rather than process implementation capability. Thus, companies spent a great amount of time and effort in the introduction of creativity management and R&D activities. However, as company's continuous investment on R&D and innovation activities did not lead to business performance, they starts to pay much attention on the effective R&D and innovation activities. Therefore, this paper tries to solve the limitation of the effectiveness of R&D activities by introducing the concept of 'creative quality'. The creative quality is executed by the creative process, which is designed for getting over the limitation of the traditional brainstorming method. This paper presents the concept so called 'creative quality management' and expects it to be an alternative to conquest the limitation of six sigma management.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.343-348
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• 2011

With the rapid and wide-spread use of mobile communications much attention has been focussed on propagation in the urban area crowed with buildings. It is often surrounded by hills, forests, and mountains. The importance of surface scattering interference between transmitters and receivers on the rough surfaces has been interested and investigated. Therefore, a prediction method is necessary to estimate the influence of rough surfaces on microwave radio propagation. Moreover, most of the mobile communications are performed based on the digital communication system rather than the analog one. In this case, we must pay more careful attention to the signal delay caused by the phase delay due to the multi-path propagation. In this paper we have analyzed numerically scattering of electromagnetic waves from Composite structures by using FVTD (Finite Volume Time Domain) method. We consider two different types of rough surfaces such as periodic and composite structures.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.109-115
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• 2019

Currently, LPWA(Low Power Wide Area) communication technology is widely used due to the development of IoT(Internet of Things) technology. Among the LPWA technologies, LoRaWAN(Long Range Wide Area Network) is widely used in many fields due to its wide coverage, stable communication speed, and low-cost modem module prices. In particular, LoRa(Long Range) can easily construct LoRaWAN with a dedicated gateway. So many organizations are building their own LoRaWAN-based networks. The LoRaWAN Gateway receives the LoRa packet transmitted from an End-device installed in the adjacent location, converts it into the Internet protocol, and sends the packet to the final destination server. Current LoRa Gateway uses a single-hop method, and each gateway must include a communication network capable of the Internet. If it is the mobile communication(i.e., WCDMA, LTE, etc.) network, it is required to pay the internet usage fee which is installed in each gateway. If the LoRa communication is frequent, the user has to spend a lot of money. We propose an idea on how to design a multi-hop protocol which enables packet routing between gateways by analyzing the LoRaWAN communication method implemented in its existing single-hop way in this paper. For this purpose, this paper provides an analysis of the standard specification of LoRaWAN and explains what was considered when such protocol was designed. In this paper, two gateways have been placed based on the functional role so as to make the multi-hop protocol realized: (i) hopping gateway which receives packets from the end-device and forwards them to another gateway; and (ii) main gateway which finally transmits packets forwarded from the hopping gateway to the server via internet. Moreover, taking into account that LoRaWAN is wireless mobile communication, a level-based routing method is also included. If the protocol proposed by this paper is applied to the LoRaWAN network, the monthly internet fee incurred for the gateway will be reduced and the reliability of data transmission will be increased.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.9
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• pp.391-398
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• 2022

As non face-to-face classes carry on discussion about learner's attention continues. To improve learning effect learner's attention is important whether non face-to-face classes or face-to-face classes. In this study a mobile application prototype inducing learner attention is developed taking account of learner emotion that is one of the factors affecting learner attention. When learner selects one of the four emotions displayed in the application, it shows the activity inducing the learner's attention related to the selected emotion. In order to evaluate the usability of the developed application, 32 middle and high school students are asked to run the application and then conduct a survey using 5 point Likert scale. The survey result indicates that there is a possibility that the developed application in this study induces learner attention as showing that the result point of 'I can pay attention' and 'I feel psychological stable' is respectively 3.56 and the result point of 'I feel useless thought disappear' is 3.6.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.3
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• pp.165-178
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• 2007

The recent progress in multimedia signal processing and transmission technologies has contributed to the extensive use of multimedia devices to watch sports games with small LCD panel. However, the most of video sequences are captured for normal viewing on standard TV or HDTV, for cost reasons, merely resized and delivered without additional editing. This may give the small-display-viewers uncomfortable experiences in understanding what is happening in a scene. For instance, in a soccer video sequence taken by a long-shot camera techniques, the tiny objects (e.g., soccer ball and players) may not be clearly viewed on the small LCD panel. Moreover, it is also difficult to recognize the contents of the scorebox which contains the elapsed time and scores. This renuires intelligent display technique to provide small-display-viewers with better experience. To this end, one of the key technologies is to determine region of interest (ROI) and display the magnified ROI on the screen, where ROI is a part of the scene that viewers pay more attention to than other regions. Examples include a region surrounding a ball in long-shot and a scorebox located in the comer of each frame. In this paper, we propose a scheme for raising viewing experiences of multimedia mobile device users. Instead of taking generic approaches utilizing visually salient features for extraction of ROI in a scene, we take domain-specific approach to exploit unique attributes of the soccer video. The proposed scheme consists of two modules: ROI determination and scorebox extraction. The experimental results show that the proposed scheme offers useful tools for intelligent video display on multimedia mobile devices.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.91-100
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• 2015

The environment of using digital devices has been developed day by day, as mobile communication network has been fast and smart phone and tablet PC have been spread. When the environment changing, the contents consumers prefer have been changing too. The Webtoon became the representative contents of 'Snack culture'. The webtoon has led the growth of cartoon market for years recently instead of the slow comics growth. And it places its elf as contents on a firm basis, as it has been adapted to another genre such as Pay, Flm, TV Drama. Now it's expected to be an extgeneration contents that will lead Han-ryu(Korean wave). Though the webtoon has important and strong presence, there is no digital archive for collecting and preserving the webtoon, Korean Cartoon Contents Agency started making 'webtoon archive', but the groundwork and the study on the webtoon that represents digital culture contents are not enough a lot. In this study, the cases on digital archiving of culture contents in Korea are researched, and the direction on webtoon archiving that has just started is also discussed. The Archiving of webtoon that can't be seperated from digital contents is connected with archiving of digital culture contents in direction where they should be headed to.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.385-388
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• 2020

At present, the payment system in Thailand changes from a paper-based system to a cashless payment system. A coin has its two sides, so the cashless payment has its advantages and disadvantages. This article describes the general advantages and disadvantages of a cashless society in Thailand in the COVID-19 situation. The cashless payment in Thailand consists of credit cards, automated teller machines, direct debit, mobile/Internet banking, e-Wallet, PromptPay, and QR code. The cashless payment is able to assist the government for tax collection accuracy and facilitates users to make financial transactions more transparent and efficient. In addition, the cashless system provides benefits to businesses in which they are able to increase sales and expand business by providing convenient, safe and faster services to customers in making payment for goods/services. It assists businesses to save time and cost of cash management and reduce the paperwork. The cashless payment made the life of students, housewives, and elderly people very easy to carry out financial transactions and there is no need to meet the financial institution staff. This payment system needs advanced technology system skills, a smartphone, and a technology facility. Finally, the cashless payment can reduce the spreading of COVID-19.

• Journal of Information Technology Services
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• v.15 no.3
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• pp.157-171
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• 2016

As unemployment rates and concerns about turnover keep growing, the need for information is also increasing. In these situations, the job reviews which share information about the company catch people's attention because they are usually created by people who worked at the company. The development of SNS and mobile environments has led to an increase in the web services that provide job reviews. For example, Jobplanet is a job review service in Korea, and Glassdoor.com offers a similar service in the US. Despite this attention, however, research utilizing job reviews is insufficient. This paper asks whether there are differences in ratios of job satisfaction factors by industry, using LDA topic modeling and co-occurrence analysis to explore the differences. Through the results of LDA, we find that the ratios of job satisfaction factors are similar by industry. At the same time, the results of co-occurrence analysis show that the co-occurrence frequency of some job satisfaction factors appears high: pay and welfare, balance of work and life, company culture. We expect that the result of this research will be helpful in comparative analysis of job satisfaction factors by industry. Furthermore, in this paper we suggest how to use the job review data in organizational behavior research.

• Journal of Auto-vehicle Safety Association
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• v.9 no.1
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• pp.13-18
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• 2017

In recent years, NCAP regulations of many countries have induced automaker to improve the vehicle crashworthiness. But, the current NCAP regulations don't cover all types of traffic accidents. And rapid-increasing market share of compact cars and SUVs has brought for both consumer and automaker to pay more attention on crash compatibility. So, many countries have tried to develop the new crash test mode and update the present crash test mode. Especially, Euro NCAP has been developing a new impact protocol of the car-to-car frontal offset impact including the crash compatibility assessment. There are plans to introduce this new protocol in 2020, and it will be replaced the current Euro NCAP frontal offset impact. The test dummy in the front seats of this new test mode will be changed from 50% Hybrid-III male to 50% THOR male. This paper will address the vehicle responses, the occupant responses and the vehicle compatibility performance from a full vehicle crash test using the new car-to-car frontal offset test protocol of Euro NCAP.