A challenge faced by the video game industry is to develop believable and more intelligent Non-Playable Characters (NPCs). To tackle this problem a low-cost and simple approach has been proposed in this research, which is the development of a gossip virtual social network for NPCs. The network allows simple individual NPCs to communicate their knowledge amongst themselves. The communication within this social network is governed by social-psychological rules. These rules are categorized into four types: Contact, whether the NPC are within a contactable range of each other; Observation, whether the NPCs actually want to talk to each other based on their personal traits; Status, the current representation of the NPCs; and Relationships which determines the long term ties of the NPCs. Evaluations of the proposed gossip virtual social network was conducted, both through statistical analysis and a survey of real users. Highly satisfactory results have been achieved.

We discuss a new high performance computing service (HPCS) platform that has been developed to provide domain-neutral computing service under the governmental support from “EDucation-research Integration through Simulation On the Net” (EDISON) project. With a first focus on technical features, we not only present in-depth explanations of the implementation details, but also describe the strengths of the EDISON platform against the successful nanoHUB.org gateway. To validate the performance and utility of the platform, we provide benchmarking results for the resource virtualization framework, and prove the stability and promptness of the EDISON platform in processing simulation requests by analyzing several statistical datasets obtained from a three-month trial service in the initiative area of computational nanoelectronics. We firmly believe that this work provides a good opportunity for understanding the science gateway project ongoing for the first time in Republic of Korea, and that the technical details presented here can be served as an useful guideline for any potential designs of HPCS platforms.

The linearity and noise required by GSM and UMTS receivers make the design of a CMOS mixer for these applications so challenging. A new technique for IP2 improvement in Zero-IF active mixers is presented in this paper. This inductor-less technique is based on canceling the parasitic capacitor of common source node of the switching transistors and synthesizing resistive impedance. Using this technique, a reconfigurable down converter mixer works from 900 MHz to 2.4 GHz is designed supporting GSM, DCS, PCS, UMTS and IEEE802.11 b-g standards. The mixer IIP2 is higher than 71 dBm in GSM and UMTS bands. The mixer conversion gain is higher that 12 dB in all frequency bands. The design is done in 65 nm CMOS technology and consumes 10 mA from a 1.2 V supply. The design meets the performance required for all mentioned standards, while its area and power is comparable with high performance single band mixers.

We present a numerical analysis of the optimal number of groups for minimizing the average paging delay. In the analysis, we consider uniform distributions for location probability conditions and apply the M/D/1 queueing model to paging message queues of cells. We also compute the lower bounds of group numbers and investigate the minimum transmission capacity under average paging delay constraints.

Model-based movement patterns play a crucial role in evaluating the performance of mobility-dependent Personal Communication Service (PCS) strategies. This study proposes a new normal walk model to represent more closely the daily movement patterns of a mobile station (MS) in PCS networks than a conventional random walk model. A drift angle θ in this model is applied to determine the relative direction in which an MS handoffs in the next one step, based on the concepts that most real trips follow the shortest path and the directions of daily motion are mostly symmetric. Hence, θ is assumed to approach the normal distribution with the parameters: µ is set to 0and σ is in the range of 5to 90. Varying σ thus redistributes the probabilities associated with θ to make the normal mobility patterns more realistic than the random ones. Experimental results verify that the proposed normal walk is correct and valid for modeling an n-layer mesh cluster of PCS networks. Moreover, when σ = 79.5, a normal walk can almost represent, and even replace, a random walk.

Over the last decade there has been a rapid growth of wireless communication technology. Among numerous wireless network architectures, the personal communication services (PCS) networks and wireless local area networks (WLAN) have attracted lots of attention. One of the core functionalities in wireless networks is the location service that provides location information for subscriber services, emergency services, and various mobile networks internal operations. In this paper, an integrated location management mechanism is proposed for heterogeneous wireless networks that combine PCS networks and WLAN. Three major functionalities in the integrated location management scheme are the determination of the WLAN connectivity for a mobile terminal, the development of a local area location scheme for WLAN, and the location prediction module for PCS networks. This mechanism not only determines the location of a mobile client more precisely, but also reduces the cost of locating. The performance evaluation is conducted to demonstrate the effectiveness of the proposed mechanism for heterogeneous wireless networks.

Future personal communication service (PCS) networks consider smaller cells to accommodate continuously growing population of subscribers. That results in frequent location update and consequently higher signaling cost. Among various schemes proposed for improving the efficiency of location management, the distance-based and the direction-based location update methods work well for just certain mobility patterns. In this paper, we propose a hybrid location update (HLU) scheme, which takes into account both the moving distance and the moving direction when deciding on updating the location. We analyze the performance of the HLU under different mobility patterns and call-to-mobility ratios based on a 2D Markov walk model. The numerical results demonstrate that the HLU scheme can achieve better performance than the distance-based or the direction-based methods applied individually.

In this paper, we consider a location management scheme using Limited Pointer forwarding from Commonly visited sites (LPC) strategy for Personal Communication Services (PCS) networks. The Commonly Visited Site (CVS) is defined as a site in which a mobile user is found with high probability. A feature of the strategy is that it skips updating location information of the mobile user, provided that the mobile user moves within its CVSs. Such a strategy is expected to significantly reduce the location update cost. We evaluate the location management cost of the LPC scheme by employing a Continuous-Time Markov Chain (CTMC) model. We show that the LPC scheme can reduce the location management cost of a highly mobile user who is found in its CVS with high probability.

A high efficient HBT MMIC power amplifier with a new on-chip bias control circuit was proposed for PCS applications. By adjusting the quiescent current in accordance with the output power levels, the average power usage efficiency of the power amplifier is improved by a factor of 1.4. The bias controlled power amplifier, depending on low (high) output power levels, shows 62(103) mA of quiescent current, 16(28) dBm output power with 7.5(35.4)% of power-added efficiency(PAE), -46(-45) dBc of adjacent-channel power ratio (ACPR), and 23.7(26.9) dB of gain

Location management is crucial for mobile systems. A mobile must be located whenever a connection is established. Thus, mobile systems must cope with frequent location updates and queries. In addition to the HLR/VLR scheme in IS-41 and GSM, the feasibility of reducing the network load caused by locating mobile users has received considerable attention. One user location algorithm called "Pointer Forwarding with Single HLR," was proposed to reduce location update cost. Thereafter, the distributed HLR scheme was proposed to prevent HLR from becoming a signal bottleneck in the signaling network. This approach eliminates the cost of updating multiple HLRs, vastly reducing the database access delay, but also introduces long pointer chain traverse that may cause large location tracking costs and long call delivery times/costs. This study proposes a efficient location tracking strategy, named, "Fast Pointer Forwarding Strategy with Distributed HLR. " This strategy ensures that the pointer chain length never exceeds one. In fact, this strategy provides an upper bound on location tracking time. Its performance is numerically analyzed. Results in this study demonstrate that our strategy can considerably reduce the complexity of implementation and the call delivery time/cost.

In previous work we have proposed a steganographic technique for gray scale images called BPCS-Steganography. We also apply this technique to full color images by decomposing the image into its three color component images and treating each as a gray scale image. This paper proposes a method to apply BPCS-Steganography to palette-based images. In palette-based images, the image data can be decomposed into color component images similar to those of full color images. We can then embed into one or more of the color component images. However, even if only one of the color component images is used for embedding, the number of colors in the palette after embedding can be over the maximum number allowed. In order to represent the image data in palette-based format, color quantization is therefore needed. We cannot change the pixel values of the color component image that contains the embedded information, but can only change the pixel values of the other color component images. We assume that the degrading of the color component2 image with information embedded is smaller than that of the color component images that are used for color reduction. We therefore embed secret information into the G component image, because the human visual system is more sensitive to changes the luminance of a color, and G has the largest contribution to luminance of the three color components. In order to reduce the number of colors, the R and B component images are then changed in a way that minimizes the square error.

A new type of triple-band antenna is introduced by combing a tab monopole antenna (TMA) and a planar inverted F antenna (PIFA). The antenna configuration is shown to operate at three discrete frequencies: GSM 900, GSM 1800 (DCS) and GSM 1900 (PCS). The performance of an antenna is presented as well as the results of the computer simulations with a software package based on the Finite Element Method. The simulated results with the real antenna's experimental results. The advantage of the design suggested in this paper is its simplicity of manufacturing and low cost.

In this letter, we consider one-to-all broadcast on distributed memory parallel computers based on message-passing, such as cluster of WSs or PCs. We present an efficient broadcast algorithm, called overlapped-two-phase broadcast (O2PB), that is an enhanced version of two-phase broadcast (2PB). The O2PB algorithm is compared with other algorithms, such as linear broadcast, tree broadcast and 2PB algorithms. According to our theoretical and experimental results, when the size of message to be broadcasted is large, the O2PB algorithm is fastest among all the algorithms. The O2PB algorithm is approximately 20% faster than the 2PB algorithm.

The rapid growth of state space in a two-dimensional (2D) random walk model imposes heavy computational load on mobility analysis of personal communication services (PCS) networks. This letter presents a novel random walk model with a compact state space by exploiting the symmetry of cellular patterns in a K-layer cluster of cells. The size of the state space is reduced to (K+1)/2(K/2+1)+1, with an asymptotic compression ratio of 12.

The cable TV (CATV) network is an ideal backbone for PCS due to its prevalent and broadcast nature. This significantly reduces the implementation costs and the handoff overheads. This paper proposes two architectures for the CATV-based PCS system. In the first architecture, each base station is equipped with multiple fixed receivers to provide fast and seamless handoffs for mobile users. Nevertheless, the hardware cost for this implementation is relative expensive. To overcome this, in the second architecture, each base station is equipped with only one tunable receiver. This simple and economic architecture suffers from the possibility of offset conflict when mobile terminals handoff between cells. Three offset assignment algorithms based on the concepts of random assignment, neighbor usage, and clustering, respectively are proposed to solve the offset conflict problem. Simulation results indicate the one with the concept of clustering performs much better than the other two schemes in terms of offset conflict probability.

The proposed method tracks the user location in a hierarchically distributed fashion. Call patterns in personal communications services (PCS) have the locality. The virtually hierarchical link (VHL) is used to support the call locality and makes the fast call set up possible. The locality consideration effectively reduces the query traffic compared with non-locality consideration.

A mobility management scheme that reduces signaling traffic load and connection setup time is a pivotal issue in designing future personal communication service (PCS) networks to satisfy Quality of Services requirements and use network resources efficiently. Particularly, required is scalable mobility management, to meet the explosive growth in number of users for the current second-generation wireless communication systems, and to materialize PCS concepts such as terminal, personal, and service mobility. Many mobility management schemes have been proposed for the reduction of signaling traffic. However, these schemes have not been sufficiently compared using a unified performance measure that is free of assumptions as to mobility model or database architecture. In this paper, we categorize the various mobility management schemes for advanced PCSs in distributed environments into four types and clarify the appropriate domain for each type. To do this, we settled on the number of signals at connection setup and location registration as a unified performance measure, since this value closely relates to connection setup time and network efficiency. We found two kinds of schemes with replicating and caching functions of user information that are extremely effective for reducing signaling load and hence connection setup time. These schemes are appropriate when the probability that a user is in his/her home area is relatively small or the connection setup rate is relatively high compared to the location registration rate. These are the most likely situations in the advanced PCS for global environments.

In this paper, we present several traffic handling schemes for improving the QoSs (quality-of-services) in a micro-cell based PCS (personal communication services) network. Traffic handling schemes are devised for the efficient use of the limited radio resources with the increasing number of users and multimedia traffic. Both mathematical analysis and computer simulations are carried out for the performance evaluation in terms of the blocking probability of new call, the forced termination probability of handoff voice and data and the average delay of data. Analytical models by bivariate Markov processes are provided. It reveals that a finite queueing scheme for handoff delay sensitive data guarantees QoS metrics, such as the blocking probability of new voice and data and forced termination probability of handoff voice and data, as well as the efficient use of radio resources. The optimal number of reserved channels for handoff delay sensitive data and the optimal number of reserved channels for handoff traffic (in reserved channel scheme) are investigated and obtained. Dynamically controlled reserved channel schemes turn out to provide no significant performance improvement.

This paper is concerned with CDMA applied to personal and mobile communications on a global basis using multiple low earth orbital satellites (LEOS). We focus our attention on some unique aspects of LEOS systems and discuss their influences on the CDMA system performance as well as the techniques for coping with these aspects. We deal with three kinds of important items that are unique to LEOS systems; Doppler frequency shift due to satellite movement, propagation delay affecting packetized data transmission and geographical nonunifomity in traffic.

This paper presents the evaluation for personal communication systems (PCS). Two types of PCS are supposed for low and high degree of mobility. The service area with 30km radius is covered by a multiple hexagonal cells, which are micro cells and macro cells for the low mobility and high mobility planes respectively. As for a traffic distribution, uniform and exponentially tapered traffic distributions are assumed. After defining the system model, cost evaluation form along with capacity has been derived. The evaluation and discussions are made in terms of cost economy, capacity and spectrum usage in various conditions. It is shown that there exist the optimum cell radius for the prescribed subscriber numbers and the integration of two systems is desirable for the support of full mobility with cost-effectiveness and spectrum efficiency.