Kyoung-Ju Noh

A QoS RED Buffer Management Scheme of Intelligent Gateway Gadget based on a Wireless LAN

The recent information technology (IT) researches aim a ubiquitous environment ultimately. We introduce an intelligent gadget network (IGN) that is a research for a personalization service, and propose a buffer management scheme of gateway gadget that uses a wireless local area network (WLAN) to bind an IGN and an external Internet network. An IGN records everyday life information of a person including an environment and a vital information, and the person can use a personalization service by the recorded information. Therefore, IGN gadgets can require a service of high data rate such as a multimedia that sends and receive with an external Internet. At this time, if a gateway gadget can not support that required data rate, it becomes a bottleneck point. When considering a transmission rate and a current established infrastructure, it is useful to implement a gateway gadget using wireless LAN. This paper proposes a buffer management scheme in medium access control (MAC) layer of gateway gadget that adopts a IEEE802.11e WLAN to connect an IGN with an external Internet network. The proposed buffer mechanism is based on the random early discard (RED) algorithm. The proposed method is simulated in the prototype board that is developed for a next generation wireless LAN standard of IEEE802.11n. The simulation results show that the buffer method in a MAC level is useful for quality of service (QoS) because it lowers drop rates and makes the drop rate of wireless communication system uniform.

Personal life logger and belonging monitor using reliable ZigBee networks

In this paper, we introduce a wearable and handheld Intelligent Gadget (IG). IG is a prototype system for implementing a concept of personalized smart object defined in SPOT. we design and implement a personal life logger and belonging monitor using IGN which provides interaction among IGs for supporting real-time online logging of personal life log and dynamic reconfiguration of personalized services. We also propose a reliable data transmission method within IGN based on ZigBee network, and show performance analysis through an experiment of transferring JPEG data.

Adaptive and dynamic tuning of the operation parameter value for QoS and fairness in wireless LAN

This paper describes an adaptive and dynamic tuning method of the operation parameter value in wireless LANs. That is, the mechanism for QoS (quality of service) in EDCA (enhanced distributed channel access) of IEEE 802.11e. For this purpose, the HC (hybrid coordinator) in QAP (QoS access point) defines the required QoS level of the traffic to service by QoS elements such as throughput and delay. And HC adjusts the operation parameter value according to the relative ratio of each QoS element value. When needed, HC readjust that parameter value dynamically using the collected data during wireless LAN service. This proposed tuning mechanism is evaluated via simulation.

Topic model-based recommendation system for media re-creation service

This paper proposes a topic model-based recommendation system that predicts a users rating score of a searched media unit for media re-creation service. The purpose of the proposed recommender is to perform a context-aware recommendation of suitable media units for a users purpose and context. For this purpose, it uses a topic vector based on the metadata of the media to compare the similarity of subject of recreated and re-creating media. In the experiment to validate the concept of the proposed recommender, the efficiency of recommendation was improved while indicating the MAE (Mean Absolute Error) is lowered without significant time consumption.

Automatic topic-based CF recommendation method considering subject similarity

This paper proposes an automatic Topic-based CF Recommendation (TCFR) method for constructing a combined media with multiple unit media. To predict the preference rating score of the retrieved unit media, the proposed method uses subject similarity of the existing media combination that has been included the unit media and the target media. The subject similarity is determined by the similarity of topic-vectors that represent a set of subject topics of the media. It distinguishes a group of similar media combinations and other one using the similarity of topic vector. The method predicts the final rating score by applying weight value for the rating score that is predicted in the each group based on the typical CF (Collaborative Filtering). In the experiment of this paper, it demonstrates that the proposed context-aware recommendation method considering the subject similarity improves the performance of recommendation more than does the typical user-based CF method.

Description and recognition based on directional motion vector for spatial hand gestures

This paper presents a description method and an adaptive DTW recognition algorithm (a-DTW) based on Directional Motion Vector (DMV) for spatial hand gestures. The a-DTW based on the classic DTW (Dynamic Time Warping) is designed to compare the degree of similarity between hand gesture segments and hand gesture commands that are defined as a sequence of DMVs. This study uses IMU (Inertial Measurement Unit) sensors such as an accelerometer and a gyroscope to separate hand gestures into a sequence of DMVs. The proposed description and recognition method are implemented and evaluated on the MCU of a test platform of wrist-band type. The experiment average recognition rate of a-DTW is more than 95% for 7 kinds of spatial hand gestures, and the recognition process has been completed within less than 20ms. By the experiment results, the proposed a-DTW recognition method is useful to improve the degree of freedom for spatial hand gestures.