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Research Collection School Of Computing and Information Systems

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Time-Bound Hierarchical Key Assignment: An Overview, Wen Tao Zhu, Robert H. Deng, Jianying Zhou, Feng Bao May 2010

Time-Bound Hierarchical Key Assignment: An Overview, Wen Tao Zhu, Robert H. Deng, Jianying Zhou, Feng Bao

Research Collection School Of Computing and Information Systems

The access privileges in distributed systems can be effectively organized as a partial-order hierarchy that consists of distinct security classes, and the access rights are often designated with certain temporal restrictions. The time-bound hierarchical key assignment problem is to assign distinct cryptographic keys to distinct security classes according to their privileges so that users from a higher class can use their class key to derive the keys of lower classes, and these keys are time-variant with respect to sequentially allocated temporal units called time slots. In this paper, we present the involved principle, survey the state of the art, and …


A Comparative Exploration Of Freebsd Bug Lifetimes, Gargi Bougie, Christoph Treude, Daniel M. Germán, Margaret-Anne Storey May 2010

A Comparative Exploration Of Freebsd Bug Lifetimes, Gargi Bougie, Christoph Treude, Daniel M. Germán, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

In this paper, we explore the viability of mining the basic data provided in bug repositories to predict bug lifetimes. We follow the method of Lucas D. Panjer as described in his paper, Predicting Eclipse Bug Lifetimes. However, in place of Eclipse data, the FreeBSD bug repository is used. We compare the predictive accuracy of five different classification algorithms applied to the two data sets. In addition, we propose future work on whether there is a more informative way of classifying bugs than is considered by current bug tracking systems.


A Scalable And Energy-Efficient Context Monitoring Framework For Mobile Personal Sensor Networks, Seungwoo Kang, Jinwon Lee, Hyukjae Jang, Youngki Lee, Souneil Park, Junehwa Song May 2010

A Scalable And Energy-Efficient Context Monitoring Framework For Mobile Personal Sensor Networks, Seungwoo Kang, Jinwon Lee, Hyukjae Jang, Youngki Lee, Souneil Park, Junehwa Song

Research Collection School Of Computing and Information Systems

The key feature of many emerging pervasive computing applications is to proactively provide services to mobile individuals. One major challenge in providing users with proactive services lies in continuously monitoring users’ context based on numerous sensors in their PAN/BAN environments. The context monitoring in such environments imposes heavy workloads on mobile devices and sensor nodes with limited computing and battery power. We present SeeMon, a scalable and energy-efficient context monitoring framework for sensor-rich, resource-limited mobile environments. Running on a personal mobile device, SeeMon effectively performs context monitoring involving numerous sensors and applications. On top of SeeMon, multiple applications on the …


Exploiting Query Logs For Cross-Lingual Query Suggestions., Wei Gao, Cheng Niu, Jian-Yun Nie, Ming Zhou, Kam-Fai Wong, Hsiao-Wuen Hon May 2010

Exploiting Query Logs For Cross-Lingual Query Suggestions., Wei Gao, Cheng Niu, Jian-Yun Nie, Ming Zhou, Kam-Fai Wong, Hsiao-Wuen Hon

Research Collection School Of Computing and Information Systems

Query suggestion aims to suggest relevant queries for a given query, which helps users better specify their information needs. Previous work on query suggestion has been limited to the same language. In this article, we extend it to cross-lingual query suggestion (CLQS): for a query in one language, we suggest similar or relevant queries in other languages. This is very important to the scenarios of cross-language information retrieval (CLIR) and other related cross-lingual applications. Instead of relying on existing query translation technologies for CLQS, we present an effective means to map the input query of one language to queries of …


Efficient Unidirectional Proxy Re-Encryption, Sherman Chow, Weng Jian, Yanjiang Yang, Robert H. Deng May 2010

Efficient Unidirectional Proxy Re-Encryption, Sherman Chow, Weng Jian, Yanjiang Yang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Proxy re-encryption (PRE) allows a semi-trusted proxy to convert a ciphertext originally intended for Alice into one encrypting the same plaintext for Bob. The proxy only needs a re-encryption key given by Alice, and cannot learn anything about the plaintext encrypted. This adds flexibility in various applications, such as confidential email, digital right management and distributed storage. In this paper, we study unidirectional PRE, which the re-encryption key only enables delegation in one direction but not the opposite. In PKC 2009, Shao and Cao proposed a unidirectional PRE assuming the random oracle. However, we show that it is vulnerable to …


Awareness 2.0: Staying Aware Of Projects, Developers And Tasks Using Dashboards And Feeds, Christoph Treude, Margaret-Anne Storey May 2010

Awareness 2.0: Staying Aware Of Projects, Developers And Tasks Using Dashboards And Feeds, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Software development teams need to maintain awareness of various different aspects ranging from overall project status and process bottlenecks to current tasks and incoming artifacts. Currently, there is a lack of theoretical foundations to guide tool selection and tool design to best support awareness tasks. In this paper, we explore how the combination of highly configurable project, team and contributor dashboards along with individual event feeds is used to accomplish extensive awareness. Our results stem from an empirical study of several large development teams, with a detailed study of a team of 150 developers and additional data from another four …


Innovative Entrepreneurs Workbook, Arcot Desai Narasimhalu May 2010

Innovative Entrepreneurs Workbook, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

The workbook provides a step by step approach to identifying innovation opportunities and the key aspects of Innovation development


Shifting Inference Control To User Side: Architecture And Protocol, Yanjiang Yang, Yingjiu Li, Robert H. Deng, Feng Bao Apr 2010

Shifting Inference Control To User Side: Architecture And Protocol, Yanjiang Yang, Yingjiu Li, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Inference has been a longstanding issue in database security, and inference control, aiming to curb inference, provides an extra line of defense to the confidentiality of databases by complementing access control. However, in traditional inference control architecture, database server is a crucial bottleneck, as it enforces highly computation-intensive auditing for all users who query the protected database. As a result, most auditing methods, though rigorously studied, are not practical for protecting large-scale real-world database systems. In this paper, we shift this paradigm by proposing a new inference control architecture, entrusting inference control to each user's platform that is equipped with …


Efficient Skyline Maintenance For Streaming Data With Partially-Ordered Domains, Yuan Fang, Chee-Yong Chan Apr 2010

Efficient Skyline Maintenance For Streaming Data With Partially-Ordered Domains, Yuan Fang, Chee-Yong Chan

Research Collection School Of Computing and Information Systems

We address the problem of skyline query processing for a count-based window of continuous streaming data that involves both totally- and partially-ordered attribute domains. In this problem, a fixed-size buffer of the N most recent tuples is dynamically maintained and the key challenge is how to efficiently maintain the skyline of the sliding window of N tuples as new tuples arrive and old tuples expire. We identify the limitations of the state-of-the-art approach STARS, and propose two new approaches, STARS+ and SkyGrid, to address its drawbacks. STARS+ is an enhancement of STARS with three new optimization techniques, while SkyGrid is …


Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis Apr 2010

Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis

Research Collection School Of Computing and Information Systems

Consider a set of customers (e.g., WiFi receivers) and a set of service providers (e.g., wireless access points), where each provider has a capacity and the quality of service offered to its customers is anti-proportional to their distance. The capacity constrained assignment (CCA) is a matching between the two sets such that (i) each customer is assigned to at most one provider, (ii) every provider serves no more customers than its capacity, (iii) the maximum possible number of customers are served, and (iv) the sum of Euclidean distances within the assigned provider-customer pairs is minimized. Although max-flow algorithms are applicable …


Practical Id-Based Encryption For Wireless Sensor Network, Cheng-Kang Chu, Joseph K. Liu, Jianying Zhou, Feng Bao, Robert H. Deng Apr 2010

Practical Id-Based Encryption For Wireless Sensor Network, Cheng-Kang Chu, Joseph K. Liu, Jianying Zhou, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper, we propose a new practical identity-based encryption scheme which is suitable for wireless sensor network (WSN). We call it Receiver-Bounded Online/Offline Identity-based Encryption (RB-OOIBE). It splits the encryption process into two parts -- the offline and the online part. In the offline part, all heavy computations are done without the knowledge of the receiver's identity and the plaintext message. In the online stage, only light computations such as modular operation and symmetric key encryption are required, together with the receiver's identity and the plaintext message. Moreover, since each offline ciphertext can be re-used for the same receiver, …


Adaptive Ensemble Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Steven C. H. Hoi, Wee Keong Ng Apr 2010

Adaptive Ensemble Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Steven C. H. Hoi, Wee Keong Ng

Research Collection School Of Computing and Information Systems

Classification in P2P networks has become an important research problem in data mining due to the popularity of P2P computing environments. This is still an open difficult research problem due to a variety of challenges, such as non-i.i.d. data distribution, skewed or disjoint class distribution, scalability, peer dynamism and asynchronism. In this paper, we present a novel P2P Adaptive Classification Ensemble (PACE) framework to perform classification in P2P networks. Unlike regular ensemble classification approaches, our new framework adapts to the test data distribution and dynamically adjusts the voting scheme by combining a subset of classifiers/peers according to the test data …


Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis Apr 2010

Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis

Research Collection School Of Computing and Information Systems

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations are fixed), …


A Verification System For Interval-Based Specification Languages, Chunqing Chen, Jin Song Dong, Jun Sun, Andrew P. Martin Apr 2010

A Verification System For Interval-Based Specification Languages, Chunqing Chen, Jin Song Dong, Jun Sun, Andrew P. Martin

Research Collection School Of Computing and Information Systems

Interval-based specification languages have been used to formally model and rigorously reason about real-time computing systems. This usually involves logical reasoning and mathematical computation with respect to continuous or discrete time. When these systems are complex, analyzing their models by hand becomes error-prone and difficult. In this article, we develop a verification system to facilitate the formal analysis of interval-based specification languages with machine-assisted proof support. The verification system is developed using a generic theorem prover, Prototype Verification System (PVS). Our system elaborately encodes a highly expressive set-based notation, Timed Interval Calculus (TIC), and can rigorously carry out the verification …


Data Mining Based Predictive Models For Overall Health Indices, Ridhima Rajkumar, Kyong Jin Shim, Jaideep Srivastava Apr 2010

Data Mining Based Predictive Models For Overall Health Indices, Ridhima Rajkumar, Kyong Jin Shim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

In this study, we infer health care indices of individuals using their pharmacy medical and prescription claims. Specifically, we focus on the widely used Charlson Index. We use data mining techniques to formulate the problem of classifying Charlson Index (CI) and build predictive models to predict individual health index score. First, we present comparative analyses of several classification algorithms. Second, our study shows that certain ensemble algorithms lead to higher prediction accuracy in comparison to base algorithms. Third, we introduce cost-sensitive learning to the classification algorithms and show that the inclusion of cost-sensitive learning leads to improved prediction accuracy. The …


Generating Synonyms Based On Query Log Data, Stelios Paparizos, Tao Cheng, Hady W. Lauw Apr 2010

Generating Synonyms Based On Query Log Data, Stelios Paparizos, Tao Cheng, Hady W. Lauw

Research Collection School Of Computing and Information Systems

An approach is described for generating synonyms to supplement at least one information item, such as, in one case, a set of related items. The approach can involve an expansion phase, a clean-up phase, and a reduction phase. In the expansion phase, the approach identifies, for each related item, a set of initial synonym candidates. In the clean-up phase, the approach removes noise from the set of initial synonym candidates (if such noise exists), to provide a set of filtered synonym candidate items. In the reduction phase, the approach ranks and applies a threshold (or thresholds) to the set of …


Model-Based Methods For Linking Web Service Choreography And Orchestration, Jun Sun, Yang Liu, Jin Song Dong, Geguang Pu, Tian Huat Tan Mar 2010

Model-Based Methods For Linking Web Service Choreography And Orchestration, Jun Sun, Yang Liu, Jin Song Dong, Geguang Pu, Tian Huat Tan

Research Collection School Of Computing and Information Systems

In recent years, many Web service composition languages have been proposed. Web service choreography describes collaboration protocols of cooperating Web service participants from a global view. Web service orchestration describes collaboration of the Web services in predefined patterns based on local decision about their interactions with one another at the message/execution level. In this work, we present model-based methods to close the gap between the two views. Building on the strength of model checking techniques, Web service choreography and orchestration are verified against temporal properties or against each other (to show that they are consistent). Specialized optimization techniques are developed …


Local Coordination Under Bounded Rationality: Coase Meets Simon, Finds Hayek, C. Jason Woodard Mar 2010

Local Coordination Under Bounded Rationality: Coase Meets Simon, Finds Hayek, C. Jason Woodard

Research Collection School Of Computing and Information Systems

This paper explores strategic behavior in a network of firms using an agent-based model. The model exhibits a tension between economic efficiency and the stability of the network in the face of incentives to change its configuration. This tension is to be expected because the conditions of the Coase theorem are violated: the boundedly rational firms in the model lack the ability to discover efficient network configurations or achieve them through collective action. In computational experiments, as predicted by theory, firms frequently became locked into inefficient outcomes or endless cycles of mutual frustration. However, simple institutional innovations such as property …


Creating An Immersive Game World With Evolutionary Fuzzy Cognitive Maps, Yundong Cai, Ah-Hwee Tan, Zhiqi Shen, Boyang Li Mar 2010

Creating An Immersive Game World With Evolutionary Fuzzy Cognitive Maps, Yundong Cai, Ah-Hwee Tan, Zhiqi Shen, Boyang Li

Research Collection School Of Computing and Information Systems

An increasing number of serious games have been developed to enhance the user experiences in education and training. In order to bridge the gap of game experiences in the virtual environment and in the real life, it is crucial to generate believable characters and contexts in real-time. However, the variables to be simulated for a large-scale serious game are numerous. These variables are involved in complex causal relationships and their values change over time. In view that world modeling has not been well addressed with conventional models, this paper uses a computational model Evolutionary Fuzzy Cognitive Map (EFCM) to model …


A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong Mar 2010

A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong

Research Collection School Of Computing and Information Systems

This paper presents a self-organizing neural architecture that integrates the features of belief, desire, and intention (BDI) systems with reinforcement learning. Based on fusion Adaptive Resonance Theory (fusion ART), the proposed architecture provides a unified treatment for both intentional and reactive cognitive functionalities. Operating with a sense-act-learn paradigm, the low level reactive module is a fusion ART network that learns action and value policies across the sensory, motor, and feedback channels. During performance, the actions executed by the reactive module are tracked by a high level intention module (also a fusion ART network) that learns to associate sequences of actions …


Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu Mar 2010

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Research Collection School Of Computing and Information Systems

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …


Efficient Verification Of Shortest Path Search Via Authenticated Hints, Man Lung Yiu, Yimin Lin, Kyriakos Mouratidis Mar 2010

Efficient Verification Of Shortest Path Search Via Authenticated Hints, Man Lung Yiu, Yimin Lin, Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Shortest path search in transportation networks is unarguably one of the most important online search services nowadays (e.g., Google Maps, MapQuest, etc), with applications spanning logistics, spatial optimization, or everyday driving decisions. Often times, the owner of the road network data (e.g., a transport authority) provides its database to third-party query services, which are responsible for answering shortest path queries posed by their clients. The issue arising here is that a query service might be returning sub-optimal paths either purposely (in order to serve its own purposes like computational savings or commercial reasons) or because it has been compromised by …


Medially: A Provenance-Aware Remote Health Monitoring Middleware, Atanu Roy Chowdhury, Ben Falchuk, Archan Misra Mar 2010

Medially: A Provenance-Aware Remote Health Monitoring Middleware, Atanu Roy Chowdhury, Ben Falchuk, Archan Misra

Research Collection School Of Computing and Information Systems

This paper presents MediAlly, a middleware for supporting energy-efficient, long-term remote health monitoring. Data is collected using physiological sensors and transported back to the middleware using a smart phone. The key to MediAlly's energy efficient operations lies in the adoption of an Activity Triggered Deep Monitoring (ATDM) paradigm, where data collection episodes are triggered only when the subject is determined to possess a specified context. MediAlly supports the on-demand collection of contextual provenance using a novel low-overhead provenance collection sub-system. The behaviour of this sub-system is configured using an application-defined context composition graph. The resulting provenance stream provides valuable insight …


A Multi-Key Pirate Decoder Against Traitor Tracing Schemes, Yongdong Wu, Robert H. Deng Mar 2010

A Multi-Key Pirate Decoder Against Traitor Tracing Schemes, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper we introduce an architecture for a multi-key pirate decoder which employs decryption keys from multiple traitors. The decoder has built-in monitoring and self protection functionalities and is capable of defeating most multiple-round based traitor tracing schemes such as the schemes based on the black-box confirmation method. In particular, the proposed pirate decoder is customized to defeat the private key and the public key fully collusion resistant traitor tracing (FTT) schemes, respectively. We show how the decoder prolongs a trace process so that the tracer has to give up his effort. FTT schemes are designed to identify all …


Probabilistic Public Key Encryption With Equality Test, Guomin Yang, Chik How Tan, Qiong Huang, Duncan S. Wong Mar 2010

Probabilistic Public Key Encryption With Equality Test, Guomin Yang, Chik How Tan, Qiong Huang, Duncan S. Wong

Research Collection School Of Computing and Information Systems

We present a (probabilistic) public key encryption (PKE) scheme such that when being implemented in a bilinear group, anyone is able to check whether two ciphertexts are encryptions of the same message. Interestingly, bilinear map operations are not required in key generation, encryption or decryption procedures of the PKE scheme, but is only required when people want to do an equality test (on the encrypted messages) between two ciphertexts that may be generated using different public keys. We show that our PKE scheme can be used in different applications such as searchable encryption and partitioning encrypted data. Moreover, we show …


Efficient Cca-Secure Pke From Identity-Based Techniques, Junzuo Lai, Robert H. Deng, Shengli Liu, Weidong Kou Mar 2010

Efficient Cca-Secure Pke From Identity-Based Techniques, Junzuo Lai, Robert H. Deng, Shengli Liu, Weidong Kou

Research Collection School Of Computing and Information Systems

Boneh, Canetti, Halevi, and Katz showed a general method for constructing CCA-secure public key encryption (PKE) from any selective-ID CPA-secure identity-based encryption (IBE) schemes. Their approach treated IBE as a black box. Subsequently, Boyen, Mei, and Waters demonstrated how to build a direct CCA-secure PKE scheme from the Waters IBE scheme, which is adaptive-ID CPA secure. They made direct use of the underlying IBE structure, and required no cryptographic primitive other than the IBE scheme itself. However, their scheme requires long public key and the security reduction is loose. In this paper, we propose an efficient PKE scheme employing identity-based …


K-Anonymity In The Presence Of External Databases, Dimitris Sacharidis, Kyriakos Mouratidis, Dimitris Papadias Mar 2010

K-Anonymity In The Presence Of External Databases, Dimitris Sacharidis, Kyriakos Mouratidis, Dimitris Papadias

Research Collection School Of Computing and Information Systems

The concept of k-anonymity has received considerable attention due to the need of several organizations to release microdata without revealing the identity of individuals. Although all previous k-anonymity techniques assume the existence of a public database (PD) that can be used to breach privacy, none utilizes PD during the anonymization process. Specifically, existing generalization algorithms create anonymous tables using only the microdata table (MT) to be published, independently of the external knowledge available. This omission leads to high information loss. Motivated by this observation we first introduce the concept of k-join-anonymity (KJA), which permits more effective generalization to reduce the …


Further Exploration On Relationship Between Crisp Sets And Fuzzy Sets, Zhaoxia Wang, Quan Wang, Ming Bai, Chen Zeng-Qiang, Zhen Sun Feb 2010

Further Exploration On Relationship Between Crisp Sets And Fuzzy Sets, Zhaoxia Wang, Quan Wang, Ming Bai, Chen Zeng-Qiang, Zhen Sun

Research Collection School Of Computing and Information Systems

This paper employs the concept of fuzzify upgrade operator to describe the relationship between crisp sets, fuzzy sets and higher order fuzzy sets, such as type-2 fuzzy sets. Theory analysis and case studies demonstrate that a crisp set can be represented by a type-1 fuzzy set, a type-1 fuzzy set can be represented by a type-2 fuzzy set, and a type-n (n>=2) fuzzy set can be represented by a type-(n+1) (n>=2) fuzzy set. The fuzzify upgrade operator makes crisp sets, type-1 fuzzy sets, type-2 fuzzy sets and any fuzzy sets much more accessible to all readers. The relationship …


Privacy-Preserving Similarity-Based Text Retrieval, Hwee Hwa Pang, Jialie Shen, Ramayya Krishnan Feb 2010

Privacy-Preserving Similarity-Based Text Retrieval, Hwee Hwa Pang, Jialie Shen, Ramayya Krishnan

Research Collection School Of Computing and Information Systems

Users of online services are increasingly wary that their activities could disclose confidential information on their business or personal activities. It would be desirable for an online document service to perform text retrieval for users, while protecting the privacy of their activities. In this article, we introduce a privacy-preserving, similarity-based text retrieval scheme that (a) prevents the server from accurately reconstructing the term composition of queries and documents, and (b) anonymizes the search results from unauthorized observers. At the same time, our scheme preserves the relevance-ranking of the search server, and enables accounting of the number of documents that each …


Efficient Valid Scope For Location-Dependent Spatial Queries In Mobile Environments, Ken C. K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger, Baihua Zheng Feb 2010

Efficient Valid Scope For Location-Dependent Spatial Queries In Mobile Environments, Ken C. K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger, Baihua Zheng

Research Collection School Of Computing and Information Systems

In mobile environments, mobile clients can access information with respect to their locations by submitting Location-Dependent Spatial Queries (LDSQs) to Location-Based Service (LBS) servers. Owing to scarce wireless channel bandwidth and limited client battery life, frequent LDSQ submission from clients must be avoided. Observing that LDSQs issued from a client located at nearby positions would likely return the same query results, we explore the idea of valid scope, which represents a spatial area in which a set of LDSQs will retrieve exactly the same set of query results. With a valid scope derived and an LDSQ result cached, a client …