• 대한산업공학회지
• /
• 제32권2호
• /
• pp.120-125
• /
• 2006

Since Korean government has implemented the "Number Portability System" in the domestic mobile communications market, mobile communication companies have been striving to hold onto existing customers and at the same time to attract new customers. This paper presents a competing risk model that considers the characteristics of a customer in order to predict the customer's life under the "Number Portability System." Three competing risks considered are pricing policy, quality of communication, and usefulness of service. It was observed that the customers who pay more are less sensitive on pricing policy younger people are less sensitive than older people to the quality of communication and women are more sensitive than men to the degree of usefulness of service. We expect that the result of this study can be used as a guideline for effective management of mobile phone customers under the Number Portability System.

• 대한인간공학회지
• /
• 제26권2호
• /
• pp.15-20
• /
• 2007

The purpose of this study is to compare assessment techniques for Korean characters entry methods of mobile phones. This study was performed based on survey of relevant existing studies. The assessment techniques were classified into three: 1) predicting entry time using conceptual models such as Fitts' law, Hick-Hyman's law and KLM-GOMS model (conceptual model); 2) counting the number of pressing button(number of pressing button); and 3) measuring performance or rating subjective measures using real mobile phones(real mobile phone). The comparison revealed that the assessment results were different depending upon the techniques used. The results from the conceptual model using only Fitts' law and the number of pressing button were opposite to those from techniques of the real mobile phone and conceptual model using Fitts' and Hick-Hyman's laws. Based on this result and suggestions provided by the literature, it is recommended that for more precisely assessing interfaces of mobile phones such as Korean characters entry method, real mobile phones be used instead of the conceptual models.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권11호
• /
• pp.2849-2865
• /
• 2012

In order to block mobile junk messages automatically, many studies on spam filters have applied machine learning algorithms. Most previous research focused only on the accuracy rate of spam filters from the view point of the algorithm used, not on individual user's preferences. In terms of individual taste, the spam filters implemented on a mobile device have the advantage over spam filters on a network node, because it deals with only incoming messages on the users' phone and generates no additional traffic during the filtering process. However, a spam filter on a mobile phone has to consider the consumption of resources, because energy, memory and computing ability are limited. Moreover, as time passes an increasing number of feature words are likely to exhaust mobile resources. In this paper we propose a spam filter model distributed between a users' computer and smart phone. We expect the model to follow personal decision boundaries and use the uniform resources of smart phones. An authorized user's computer takes on the more complex and time consuming jobs, such as feature selection and training, while the smart phone performs only the minimum amount of work for filtering and utilizes the results of the information calculated on the desktop. Our experiments show that the accuracy of our method is more than 95% with Na$\ddot{i}$ve Bayes and Support Vector Machine, and our model that uses uniform memory does not affect other applications that run on the smart phone.

• 정보보호학회논문지
• /
• 제22권3호
• /
• pp.537-544
• /
• 2012

최근 무선 전산망 인프라를 발판으로 스마트폰의 사용자가 크게 증가하고 있다. 이와 함께 스마트폰의 악성코드도 함께 급증하여 개인정보 유출, 과금 부과 등의 피해가 속출하고 있다. 무선전산망 환경의 보안 위협에 대처하기 위해 WIPS, MDM과 같은 무선 전산망 및 무선 단말 기기를 관리하기 위한 솔루션이 시판되고 있으나 이는 기업이나 대규모 사업자를 위한 솔루션으로 일반 스마트폰 사용자에게는 제한적이며 다양한 경로로 유포되는 알려지지 않은 악성코드를 탐지하는데 어려움이 있다. 본 논문에서는 악성코드 유형에 따른 행위 분석을 바탕으로 스마트폰 시스템 점검을 수행하여 악성 코드 감염 여부를 판별할 수 있는 기초 자료를 제공하며, 악성 코드 확산을 방지하기 위한 블랙리스트 관리 기능, 악성코드 채증 기능이 포함된 모바일 보안 진단 시스템을 제안한다.

• 음성과학
• /
• 제12권3호
• /
• pp.105-114
• /
• 2005

It was verified that a speaker verification system improved its performances of EER by regularizing log likelihood ratio, using background speaker models. Recently the wireless mobile phones are becoming more dominant communication terminals than wired phones. So the need for building a speaker verification system on mobile phone is increasing abruptly. Therefore in this paper, we had some experiments to examine the performance of speaker verification based on mobile phone's voices. Especially we are focused on the performance variations in EER(Equal Error Rate) according to several background speaker's characteristics, such as selecting methods(MSC, MIX), number of background speakers, aging factor of speech database. For this, we constructed a speaker verification system that uses GMM(Gaussin Mixture Model) and found that the MIX method is generally superior to another method by about 1.0% EER. In aspect of number of background speakers, EER is decreasing in proportion to the background speakers populations. As the number is increasing as 6, 10 and 16, the EERs are recorded as 13.0%, 12.2%, and 11.6%. An unexpected results are happened in aging effects of the speech database on the performance. EERs are measured as 4%, 12% and 19% for each seasonally recorded databases from session 1 to session 3, respectively, where duration gap between sessions is set by 3 months. Although seasons speech database has 10 speakers and 10 sentences per each, which gives less statistical confidence to results, we confirmed that enrolled speaker models in speaker verification system should be regularly updated using the ongoing claimant's utterances.

• 한국정보통신학회논문지
• /
• 제23권11호
• /
• pp.1471-1477
• /
• 2019

스마트폰에는 현재 다양한 보안 방식이 사용되고 있다. 그중에서도 핀 번호와 패턴 잠금 방식은 초기 스마트폰부터 사용되었을 정도로 오래 사용되었다. 하지만 패턴 잠금 방식은 오래 사용된 만큼 보안이 취약하다. 핀 번호 방식의 보안 강도가 약간 높은 정도라면 패턴 잠금 방식은 중간 정도에 그친다. 그럼에도 많은 스마트폰 사용자들은 패턴 잠금 방식을 이용하고 있는데 아직 생체보안을 지원하지 않는 기종을 사용하는 사용자가 있기 때문이다. 생체보안을 지원하지 않는 기종에서 제일 편리한 보안 방식은 패턴 잠금 방식이다. 그러나 기존의 패턴 잠금 방식은 Shoulder surfing attack과 Smudge attack에 취약하다. 따라서 패턴 잠금 방식의 편리성을 유지하면서 동시에 기존 방식의 취약점을 해결하는 방식을 제안하고자 한다. 제안하는 방식은 화면에 배치되는 각각의 점을 원형으로 배치한 뒤 무작위로 숫자를 부여하는 잠금 방식이다. 본 방식을 도입하게 된다면 기존의 취약점을 상당히 해결할 수 있다. 즉, 기존의 패턴 잠금 방식에 비해 보안성을 높일 수 있다.

• 사상체질의학회지
• /
• 제13권3호
• /
• pp.31-39
• /
• 2001

Bandwidth and Pitch Range are very important in the area of distinguish of phone which is one of many areas of phonetics and distinguish the individual way of phone. So if each constitution has a trait in its phone, they are important to judge the constitutions. In this report we try to understand the relativity between constitutions and Formant Bandwidth, Pitch Range and the number of syllables in a minute which are important to distinguish the phone. And we try to make judging the constitutions objective. 1. We analyzed Formant Bandwidth and there are some differences between constitutions but it doesn't have any importance in the statistics. 2. We analyzed Pitch Range and there are some differences between constitutions but it doesn't have any importance in the statistics. 3. We analyzed the number of syllables in a minute and there are some differences between constitutions but it doesn't have any importance in the statistics. As mentioned above there are differences between constitutions in Formant Bandwidth, Pitch Range and the numbers of syllables in a minute, but they don't have any importance in the statistics. However if we increase the number of samples and remove noise, there will be great possibility to find some important meanings.

• 디지털콘텐츠학회 논문지
• /
• 제12권4호
• /
• pp.585-592
• /
• 2011

경매 매물 정보시스템은 수요자의 상황과 특성에 맞춰 원하는 경매매물의 고급 정보만을 제공하는 것을 목표로 한다. 특히, 시시각각으로 변하는 조회수와 같은 실시간 정보와 경매가 예측을 위한 고도의 분석결과를 제공받기 위해서 상황인식에 기반한 모바일 정보시스템이 요구된다. 이에 따라 본 연구는 스마트폰 환경에서 수요자의 위치, 특정 매물 조회수, 현재 입찰자 수 등과 같은 경매정보를 제공해주는 상황인식 기반의 경매매물 정보시스템을 연구한다.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
• /
• pp.81-85
• /
• 2004

This study analyzes strategy and main contents between each business market by mobile phone Number Portability. And, grasps what each mobile company customer satisfaction factors is effected on mobile phone Number Portability and estimates relative importance about the factors and understand counter strategies by these factors. Concretely, this paper searched the important quality factor by frequency analysis, factor analysis, regression analysis and path analysis etc. And The sample data is subscriber using mobile communication service of the existing mobile communication company (SKT, KTF, LGT)

• 한국멀티미디어학회논문지
• /
• 제21권8호
• /
• pp.925-933
• /
• 2018

In this paper, we propose a new smart ordering application system for granting the customer numbers. The proposed system assigns sequence number of customers who visit at offline store as using speaker and microphone of smart device. This system has more advantage than the existing ordering system. Because the proposed system does not need any customer information like as phone number or SNS ID, it can protect customer privacy information. In this system, we use high frequency which is inaudible to the human ear as communication signal between speaker and microphone. To confirm performance evaluation, we perform a test with ten smart devices like as iPhone 6, 7, 8, Galaxy s8 and the result shown a success rate of 98.7 percent. Therefore, the proposed system can be useful service technology at the various offline store which need to assign a sequence number for customers, because many customers visit at the store.