• Title/Summary/Keyword: mobile-aware service

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Mobility-Aware Interference Avoidance Scheme for Vehicular WLANs

  • Park, Lai-Hyuk;Na, Woong-Soo;Lee, Gun-Woo;Lee, Chang-Ha;Park, Chang-Yun;Cho, Yong-Soo;Cho, Sung-Rae
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.12
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    • pp.2272-2293
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    • 2011
  • Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.

Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation (보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법)

  • Kwon, Oh-Byung
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

A Empirical Study on Applying Ubiquitous Technology for Gas Safety Management (U-기반 가스안전관리의 기술을 적용을 위한 실증적 연구)

  • Oh, Jeong-Seok;Choi, Kyung-Suhk;Kwon, Jeong-Rock
    • Journal of the Korean Institute of Gas
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    • v.12 no.2
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    • pp.63-68
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    • 2008
  • The ubiquitous technology is capable of innovating various area to constructing intelligent and network to all objects. This technology can construct network infrastructure to facilities for applying legacy industry and need to develop intelligent service that analyze context-aware through network. This paper derive and propose the introduction range of ubiquitous technology, which should be testified and analyzed network, and studied the detection and analysis of information for managing gas facilities. We investigate the current status of gas facilities and automatic reading system, testing and analyzing wireless personal area network and mobile communication by scalability, self-configuration, connection in underground. Furthermore, we propose modelization method for intelligent service and derive the introduction range for applying ubiquitous technologies for managing gas facilities.

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A study on ODDMRP clustering scheme of Ad hoc network by using context aware information (상황정보를 이용한 ad hoc network의 ODDMRP clustering 기법에 관한 연구)

  • Chi, Sam-Hyun;Lee, Kang-Whan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.05a
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    • pp.890-893
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    • 2008
  • 자율성 및 이동성 갖는 네트워크 구조의 하나인 MANET(Mobile Ad-Hoc Networks)은 각 node들은 그 특성에 따라서 clustering service을 한다. node의 전송과정 중 path access에 대하여 중요성 또한 강조되고 있다. 일반적인 무선 네트워크 상에서의 node들은 clustering을 하게 되는데 그 과정에서 발생되는 여러 가지 문제점을 가지고 전송이 이루어진다. 모든 node들이 송, 수신상의 전송 범위(Beam forming area)가지고 있으며, 이러한 각 node들의 전송범위 내에 전송이 이루어지는 전통적인 전송기술 mechanism을 찾는다. 이러한 전송상황에서의 송신하는 node와 수신된 node간에 발생되고 있는 중복성의 문제점으로 즉, 상호적용에 의한 네트워크 duplicate(overlapping)이 크게 우려가 되고 있다. 이러한 전송상의 전송 범위 중첩, node간의 packet 간섭현상, packet의 중복수신 및 broadcasting의 storming현상이 나타난다. 따라서 본 논문에서는 상황정보의 속성을 이용한 계층적 상호 head node들의 접근된 위치와 연계되는 전송속도, 보존하고 있는 head node들의 에너지 source value, doppler효과를 통한 head node의 이동방향 등 분석한다. 분석된 방법으로 전송상의 계층적 path가 구성된 경험적 path 속성을 통한 네트워크 connectivity 신뢰성을 극대화 할 뿐만 아니라 네트워크의 전송 범위 duplicate을 사전에 줄일 수 있고 전송망의 최적화를 유지할 수 있는 기법의 하나인 상황정보를 이용한 ad hoc network의 ODDMRP(Ontology Doppler effect-based Dynamic Multicast Routing Protocol) clustering 기법을 제안한다.

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Design and Implementation of Location-based Mobile Bus Guide System using Social Tagging (소셜 태깅 기술을 이용한 위치 기반 모바일 버스 안내 시스템의 설계 및 구현)

  • Shin, Hyun-Jeong;Chang, Byeong-Mo
    • Journal of Korea Multimedia Society
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    • v.15 no.2
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    • pp.281-289
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    • 2012
  • The goal of our research is to develop more effective bus information system using user generated information and social tagging. In this research, we have developed a smartphone-based bus guide system using social tagging and awareness of location. It will guide users to the nearby bus stops and provides users with information about the bus lines at the bus stops. Information around bus-stops can also be registered as tags into the system by users and can be utilized for bus information service. Simple keyword search utilizing tagging information can provide users with bus information about destinations.

Location Awareness Method using Vector Matching of RSSI in Low-Rate WPAN (저속 WPAN에서 수신신호세기의 Vector Matching을 이용한 위치 인식 방식)

  • Nam Yoon-Seok;Choi Eun-Chang;Huh Jae-Doo
    • Journal of Information Technology Applications and Management
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    • v.12 no.4
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    • pp.93-104
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    • 2005
  • Recently, RFID/USN is one of fundamental technologies in information and communications networks. Low-Rate WPAN, IEEE802.15.4 is a low-cost communication network that allows wireless connectivity in applications with limited Power and relaxed throughput requirements. Its applications are building automation, personal healthcare, industrial control, consumer electronics, and so on. Some applications require location information. Of course location awareness is useful to improve usability of data Low-Rate WPAN Is regarded as a key specification of the sensor network with the characteristics of wireless communication, computing, energy scavenging, self-networking, and etc. Unfortunately ZigBee alliance propose a lot of applications based on location aware technologies, but the specification and low-rate WPAN devices don't support anything about location-based services. RSSI ( Received Signal Strength indication) is for energy detection to associate, channel selection, and etc. RSSI is used to find the location of a potable device in WLAN. In this paper we studied indoor location awareness using vector matching of RSSI in low-Rate wireless PAN. We analyzed the characteristics of RSSI according to distance and experimented location awareness. We implemented sensor nodes with different shapes and configured the sensor network for the location awareness with 4 fixed nodes and a mobile node. We try to contribute developing location awareness method using RSSI in 3-dimension space.

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Smart Phone Picture Recognition Algorithm Using Electronic Maps of Architecture Configuration (건물 배치 전자도면을 이용한 모바일 폰의 피사체 인지 방법)

  • Yim, Jae-Geol;Joo, Jae-Hun;Lee, Gye-Young
    • The Journal of Society for e-Business Studies
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    • v.17 no.3
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    • pp.1-14
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    • 2012
  • As the techniques of electronic and information are advancing, the computing power of a smart phone is becoming more powerful and the storage capacity of a smart phone is becoming larger. As the result, various new useful services are becoming available on smart phones. The context-aware service and mobile augmented reality have recently been the most popular research topics. For those newly developed services, identifying the object in the picture taken by the camera on the phone performs an extremely important role. So, many researches of identifying pictures have been published and most of them are based on the time consuming image recognition techniques. On the contrary, this paper introduces a very fast and effective method of identifying the objects on the photo making use of the sensor data obtained from the smart phone and electronic maps. Our method estimates the line of sight of the camera with the location and orientation information provided by the smart phone. Then it finds any element of the map which intersects the line of sight. By investigating those intersecting elements, our method identifies the objects on the photo.

A Design of Handoff-aware DiffServ Scheduler in TDD/CDMA Networks (TDD/CDMA망에서 핸드오프를 지원하는 DiffServ 스케줄러 설계)

  • Zang, Seog-Ku;Kim, Young-Han
    • The KIPS Transactions:PartC
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    • v.14C no.6
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    • pp.493-502
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    • 2007
  • In this paper, we propose a handoff-aware DiffServ scheduler which intends to guarantee various QoS requirements of multimedia services for mobile nodes in TDD/CDMA based wireless networks. TDD is widely used duplexing mechanism in wireless communications. Unlike FDD, TDD allows a node to symmetrically communicate with a base station by using a single frequency band, resulting in high utilization of wireless resources. DiffServ is regarded as a relatively simple QoS support mechanism and thus it is easy to be extended. This is because DiffServ is not a per-flow based mechanisms and it does not require any signaling protocol. However, previously proposed DiffServ schedulers for wired networks can not be deployed directly into wireless networks since they do not consider properties of wireless networks. As a solution to the problem, DSS(DiffServ Supporting Scheduler) was proposed. DSS uses uplink channel, which is originally used for a node to require a base station to transmit packets, to support QoS efficiently. However, QoS does not consider handoff so that it can not support QoS for moving nodes from one cell to the other cell. Therefor. the proposed handoff support QoS mechanism is necessary for TCC/CDMA networks. The proposed scheme allows a mobile node to achieve seamless service without QoS degradation even for the handoff duration.

Design and Implementation of Query Processor for Moving Objects (이동객체를 위한 질의처리 컴포넌트의 설계 및 구현)

  • Kim, Kyoung-Sook;Kwon, O-Je;Byun, Hee-Young;Jo, Dae-Soo;Kim, Tae-Wan;Li, Ki-Joune
    • Journal of Korea Spatial Information System Society
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    • v.6 no.1 s.11
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    • pp.31-50
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    • 2004
  • With the growth of wireless communication networks and mobile devices taking in GPS, Location-Based Service(LBS) is becoming an integral part of mobile applications. LBS can deal with location-aware features such as persons holding mobile phones or vehicles equipped with GPS, and provide the users with the location information of the features. Thus it is necessary to develop moving object database systems to store, manage, and query moving objects which change their locations continuously as time passes. In this paper, we design and implement a query processing component which deals with moving objects as a key data type. For this component, we define a new SQL-like query language(called MOQL) and as a consequence, design and implement modules that analyze and execute queries. It supports various types of operators that process range queries, infer topological relations, compute trajectories, and find k-nearest neighbors. It can be used as a subsystem if other application systems which deal moving objects and also supports ADO.NET interface that can be used to interact end-users.

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Influencing Women's Actions on Cervical Cancer Screening and Treatment in Karawang District, Indonesia

  • Kim, Young-Mi;Ati, Abigael;Kols, Adrienne;Lambe, Fransisca Maria;Soetikno, Djoko;Wysong, Megan;Tergas, Ana Isabel;Rajbhandari, Presha;Lu, Enriquito
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2913-2921
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    • 2012
  • Introduction: The impact of cervical cancer prevention programs depends on persuading women to go for screening and, if needed, treatment. As part of an evaluation of a pilot project in Indonesia, qualitative research was conducted to explore the factors that influence women's decisions regarding screening and treatment and to generate practical recommendations to increase service coverage and reduce loss to follow up. Methods: Research was conducted at 7 of the 17 public health centers in Karawang District that implemented the pilot project. Interviews and focus group discussions were held with 20 women, 20 husbands, 10 doctors, 18 midwives, 3 district health officials, and 16 advocacy team members. Results: Free services and mobile outreach events encouraged women to go for screening, along with promotional efforts by community health workers, advocacy teams, and the mass media. Knowledge and perceptions were the most important barriers to screening: women were not aware of cervical cancer risks, did not know the disease was treatable, and were fatalistic. Factors facilitating treatment were social support from husbands, relatives, and friends and the encouragement and role modeling of health workers. Barriers to prompt treatment included limited access to services and the requirement for husband's consent for cryotherapy. Conclusion: As cervical cancer prevention services are scaled up throughout Indonesia, the findings suggest three strategies to expand screening coverage and ensure prompt treatment: strengthening community mobilization and advocacy activities, modifying the service delivery model to encourage a single visit approach to screening and treatment, and working to gain men's support.