• The Journal of Society for e-Business Studies
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• v.24 no.2
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• pp.71-89
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• 2019

In order to come up with satisfying product and improvement, firms use traditional marketing research methods to obtain consumers' opinions and further try to reflect them. Recently, gathering data from consumer communication platforms like internet and SNS has become popular methods. Meanwhile, with the development of information technology, mobile companies are launching new digital products for children to protect them from harmful content and provide them with necessary functions and information. Among these digital products, Kids Phone, which is a wearable device with safe functions that enable parents to learn childern's location. Kids phone is relatively cheaper and simpler than smartphone but it is noted that there are several problems such as some useless functions and frequent breakdowns. This study analyzes the reviews of Kids phones from domestic mobile companies, identifies the characteristics, strengths and weaknesses of the products, proposes improvement methods strategies for devices and services through SNS consumer analysis. In order to do that customer review data from online shopping malls was gathered and was further analyzed through text mining methods such as TF/IDF, Sentiment Analysis, and network analysis. Customer review data was gathered through crawling Online shopping Mall and Naver Blog/$Caf\acute{e}$. Data analysis and visualization was done using 'R', 'Textom', and 'Python'. Such analysis allowed us to figure out main issues and recent trends regarding kids phones and to suggest possible service improvement strategies based on sentiment analysis.

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.112-118
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• 2009

This paper proposes a rapid detection algorithm of a salient region for music video browsing system, which can be applied to mobile device and digital video recorder (DVR). The input music video is decomposed into the music and video tracks. For the music track, the music highlight including musical chorus is detected based on structure analysis using energy-based peak position detection. Using the emotional models generated by SVM-AdaBoost learning algorithm, the music signal of the music videos is classified into one of the predefined emotional classes of the music automatically. For the video track, the face scene including the singer or actor/actress is detected based on a boosted cascade of simple features. Finally, the salient region is generated based on the alignment of boundaries of the music highlight and the visual face scene. First, the users select their favorite music videos from various music videos in the mobile devices or DVR with the information of a music video's emotion and thereafter they can browse the salient region with a length of 30-seconds using the proposed algorithm quickly. A mean opinion score (MOS) test with a database of 200 music videos is conducted to compare the detected salient region with the predefined manual part. The MOS test results show that the detected salient region using the proposed method performed much better than the predefined manual part without audiovisual processing.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.163-169
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• 2020

A smart key has been used in a variety of embedded environments and there also have been attacks from a remote place by amplifying signals at a location of a user. Existing studies on defence techniques suggest multiple sensors and hash functions to improve authentication speed; these, however, increase the electricity usage and the probability of type 1 error. For these reasons, I suggest an embedded security controller based on client authentication and user movement information improving the authentication method between a controller and a host device. I applied encryption algorithm to the suggested model for communication using an Arduino board, GPS, and Bluetooth and performed authentication through path analysis utilizing user movement information for the authentication. I found that the change in usability was nonsignificant when performing actions using the suggested model by evaluating the time to encode and decode. The embedded security controller in the model can be applied to the system of a remote controller for a two-wheeled vehicle or a mobile and stationary host device; in the process of studying, I found that encryption and decryption could take less then 100ms. The later study may deal with protocols to speed up the data communication including encryption and decryption and the path data management.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.393-399
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• 2012

New and creative skills must be developed, and adapted into a lesson, to motivate learners to acquire a second language easily and enjoyment, Multimedia tools which are of interest to learners, such as; smart phones, computers, and notebooks with wireless internet compatability, will provide learners opportunities to study, and do their work practically anywhere and anytime. Recently, podcasts, which are a type of digital media, consisting of a series of audio episodes or video files, subscribed to and downloaded through web syndication, or streamed online to a computer or mobile device, are used to facilitate ESL (English as a Second Language) learning. Development of a variety of teaching methods, using multimedia tools, is needed. There are advantages and disadvantages to using a variety of multimedia tools. The current research aims to study its characteristics and application, in order to maximize their effective use, in English education. The current study suggests a ubiquitous learning environment using multimedia content tools, internet media, video teleconferencing, cyber-learning, and one-to-one videos used in conjunction with, or as a digital textbook for the English lesson. This study also investigates future educational changes, using state-of-the-art equipment for the self-learning experience, and will present a new direction in English education, through a variety of instructional devices and a marginalized class system model.

• Journal of Digital Forensics
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• v.12 no.3
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• pp.1-8
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• 2018

A random chat application is a type of social dating application that helps people find a lover or spouse by randomly connecting and providing services such as text, voice and video chat. Recently, there has been globally a rapid increase in its use due to the fact that it provides people to quick and convenient encounters at low cost. However, it is used as one of method to prostitute or to trade drugs and become a cause of violent crimes due to various criminal occurring after actual meeting between app users. For this reason, a random chat application is likely to provide proof of prostitution or drug trade and clues to arrest rape, kidnapping and murder suspects. Thus, it is necessary to analyse random chat applications from the viewpoint of digital forensics investigation, but there is no related research at all. Therefore, in this paper, we analyzed artifacts of 6 Korea random chat application's user behaviors; Ranchat, AngTalk, SsumgThing, DaTalk, EveryTalk and Sail. As a result, we found that it is remain on mobile device that time and contents of message transmission/reception, sender/receiver, friend profile and user account creation time when user is using the applications.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.148-156
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• 2011

Recently, an introduction of the cloud computing causes rapid changes in every aspect of the internet environments including hardware, operating systems, applications, and their services. As the cloud computing environment based on SaaS are being developed to a form in which web platform technology and web cloud services are converged. The digital library system also has been being developed to a service model optimized to SaaS based cloud computing environment, which are different from ASP technology. From the web interface point of view, user customization of the SaaS based cloud computing environment is the most important fact. Therefore, this research work suggests a customized web interface considering usability and accessibility so that enterprises and individual users can be able to do an effortless internet browsing under the cloud computing environment. For this purpose, usability tests were carried out as the user customized web interface design were developed and applied to the LinkSaaS website. This paper work lastly presents an UI environment on which customized interface design for individual users can be formulated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.103-110
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• 2006

Turbo code, a kind of error correction coding technique, has been used in the field of digital mobile communication system. As the number of iterations increases, it can achieves remarkable BER performance over AWGN channel environment. However, if the number of iterations Is increases in the several channel environments, any further iteration results in very little improvement, and requires much delay and computation in proportion to the number of iterations. To solve this problems, it is necessary to device an efficient criterion to stop the iteration process and prevent unnecessary delay and computation. In this paper, it proposes an efficient and simple criterion for stopping the iteration process in turbo decoding. By using variance values of noise derived from mean values of LLR in turbo decoder, the proposed algorithm can largely reduce the computation and average number of iterations without BER performance degradation. As a result of simulations, the computation of the proposed algorithm is reduced by about $66{\sim}80%$ compared to conventional algorithm. The average number of iterations is reduced by about $13.99%{\sim}15.74%$ compared to CE algorithm and about $17.88%{\sim}18.59%$ compared to SCR algorithm.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.290-295
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• 2006

지금까지 디지털 기기의 진화 과정을 볼 때 오직 기능적 발전만이 추구되고 그것을 사용하는 사용방식에 대한 진지한 고민은 부재하였다. 때문에 디지털 기기가 갖고 있는 버튼 위주의 획일적 사용방식은 사용자보다는 기기 중심의 디자인이 우선시되는 사회적 병리현상을 야기하고 있다. 반면 오랜 기간 인간이 다루어 온 전통적인 아날로그 도구들은 작업의 특성과 작업자의 상황에 맞도록 다양한 사용성을 고려하며 진화되어 왔다. 따라서 본 연구에서는 사용자들에게 익숙한 아날로그적 경험을 디지털 기기의 인터랙션 디자인에 적용시켜 보다 인간 중심적인 디지털 도구를 제안 하고자 한다. 연구의 목표는 다양한 기능이 복합된 대표적 디지털 기기인 휴대폰에 아날로그 경험을 접목시킴으로써 전통적인 도구들과 같이 디지털 기기의 자연스러운 인터랙션 스타일을 디자인하는 것이다. 이를 위하여 한정된 디바이스로 다양한 기능들을 조작해야 하는 모바일 기기에 적합한 아날로그 경험들에 대한 연구가 진행되었고, 기호와 조합으로 이루어진 카드놀이 메타포에서 그 단서를 발견할 수 있었다. 따라서 본 연구는 메타포로 제시한 카드놀이를 하며 일어나는 행위와 경험을 멀티미디어 휴대폰에 접목시켜 새로운 사용 방식을 제안하는 것이다. 예를 들어, 메뉴 선택의 경우 카드를 펼쳐 원하는 카드를 뽑으면 되는데 아래로 펼치면 그 카드의 수직 메뉴가, 옆으로 펼치면 그 카드의 수평 메뉴가 나타난다. 또 메뉴 안의 내용을 찾을 때는 카드를 뒤로 넘겨서 보게 되고 자신만의 개인적인 내용을 보고자 할 때는 카드를 은밀히 보는 듯한 행위를 취하면 된다. 즉 멀티미디어 폰 안의 내용뿐 아니라 사용하는 행위 자체도 하나의 즐거움이 되도록 카드놀이 경험을 새로운 인터랙션 스타일로 개발하여 그 가능성을 연구하였다.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.411-419
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• 2007

Mounted on mobile device, set-top box, or digital TV, EVM is a virtual machine solution that can download and execute dynamic application programs. And the SIL(Standard Intermediate Language) is intermediate language of the EVM, which has a set of opcodes for object-oriented language and a sequential language. Since the C compiler used on each platform depends on the hardware, it converts C program to objective code, and then executes. To solve this problem, our research team developed ANSI C compiler and the EVM. Our ANSI C compiler outputs the SIL code based on stack machine. This paper presents the SIL-to-C decompiler in which converts the SIL code to three address code. Thus, the decompiler allows us to verify SIL code created by ANSI C compiler, and analyze a program from C language source level.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.145-151
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• 2006

In conjunction with the rapid progress of IT(information technology) an increasing amount of data are being generated. The amount of new data is so big and the type of new data generated from clients or sensor devices needed to be in ubiquitous environment is so various that it is hard to manage and control them. Especially data to be occurred in ubiquitous environment are generated through PDA(personal digital assistant) smart phone, mobile device or sensor units etc. Therefore, to manage and control them generated from ubiquitous devices for decision making, we can use data warehouse as an integrated storage. A data warehouse integrates and aggregates data of several different DBMS into one DBMS. Also the updated data from source data have to be effectively propagated to the data warehouse. Therefore, in this paper, we proposed a mode) for an exact and efficient data management methodology in new IT paradigm environment, ubiquitous computing environment, to apply updated data on the warehouse to make decision. We also show brief result compared to conventional methodology.