Статті в журналах з теми "Mixed blocking constraints"

In this paper, we consider a job-shop scheduling problem with mixed blocking constraints. Contrary to most previous studies, where no blocking or only one type of blocking constraint was used among successive operations, we assume that, generally, we may address several different blocking constraints in the same scheduling problem depending on the intermediate storage among machines, the characteristics of the machines, the technical constraints, and even the jobs. Our objective was to schedule a set of jobs to minimize the makespan. Thus, we propose, for the first time, a mathematical model of the job-shop problem taking into account the general case of mixed blocking constraints, and the results were obtained using Mosel Xpress software. Then, after explaining why and how groups of jobs have to be processed, a blocking constraint conflict-free warranted evaluation function is proposed and tested with the particle swarm optimization and genetic algorithm methods. The results prove that we obtained a near-optimal solution to this problem in a very short time.

Permutation flowshop scheduling problem (PFSP) is a classical combinatorial optimisation problem. There exist variants of PFSP to capture different realistic scenarios, but significant modelling gaps still remain with respect to real-world industrial applications such as the cider production line. In this paper, we propose a new PFSP variant that adequately models both overlapable sequence-dependent setup times (SDST) and mixed blocking constraints. We propose a computational model for makespan minimisation of the new PFSP variant and show that the time complexity is NP Hard. We then develop a constraint-guided local search algorithm that uses a new intensifying restart technique along with variable neighbourhood descent and greedy selection. The experimental study indicates that the proposed algorithm, on a set of wellknown benchmark instances, significantly outperforms the state-of-the-art search algorithms for PFSP.

The flow shop scheduling problems with mixed blocking constraints with minimization of makespan are investigated. The Taguchi orthogonal arrays and path relinking along with some efficient local search methods are used to develop a metaheuristic algorithm based on bee colony optimization. In order to compare the performance of the proposed algorithm, two well-known test problems are considered. Computational results show that the presented algorithm has comparative performance with well-known algorithms of the literature, especially for the large sized problems.

An increased use of the high-voltage direct current (HVDC) technologies can have important effects on frequency performance and voltage stability of the receiving-end grid during normal operation as well as during blocking failure. The main reasons are the inherent characteristics of the HVDC such as its much larger capacity than thermal plants and lack of voltage supporting ability to the alternating current (AC) grid. These has led to new challenges for AC/direct current (DC) power grid operators in terms of ensuring power system security. To address these challenges, a unit commitment (UC) of the receiving-end in the AC/DC hybrid grid is presented in this paper. In the proposed model, primary frequency modulation constraints are added to provide sufficient capacity for HVDC blocking. Besides, grid security constraint after secondary frequency regulation is also considered because HVDC blocking failure would cause large range power transfer and transmission lines overload. Meanwhile, voltage stability constraints are employed to guarantee enough voltage supporting capacity from thermal plants at the HVDC feed-in area. Based on the characteristics of the model, Benders decomposition and mixed integer programming algorithm are used to get the optimal transmission power of the HVDC and schedule of thermal units. The study is done by considering the IEEE-39 and Jiangsu power grid in eastern China, containing two HVDC transmission projections respectively. The results are also validated by simulation of different HVDC blocking failure scenarios.

Does young bilingual children's code-mixing obey the same structural constraints as bilingual adults' code-mixing? The present study addresses this question using code-mixing data from 15 French–English bilingual children filmed in conversation with both parents at six-month intervals from the age of 2;0 to 3;6. The children's code-mixed utterances were examined for violations of the principles set out in the Matrix-Language Frame model (e.g. Myers-Scotton, 1993, 1997). The results show that the children obeyed all the constraints set out in the Matrix Language Frame model the majority of the time. With respect to the Morpheme Order Principle and to the interaction of Congruence and Matrix Language Blocking, they demonstrated consistent adherence with only marginal violations from the outset. In contrast, the children produced comparatively more frequent violations of the System Morpheme Principle and showed increasing adherence to this principle over time. We discuss possible explanations for the contrast between the children's performance on the System Morpheme Principle and the other constraints, which include the unequal emergence of INFL in the acquisition of French and English.

As multi-factory production models are more widespread in modern manufacturing systems, a distributed blocking flowshop scheduling problem (DBFSP) is studied in which no buffer between adjacent machines and setup time constraints are considered. To address the above problem, a mixed integer linear programming (MILP) model is first constructed, and its correctness is verified. Then, an iterated greedy-algorithm-blending multi-factory collaboration mechanism (mIG) is presented to optimize the makespan criterion. In the mIG algorithm, a rapid evaluation method is designed to reduce the time complexity, and two different iterative processes are selected by a certain probability. In addition, collaborative interactions between cross-factory and inner-factory are considered to further improve the exploitation and exploration of mIG. Finally, the 270 tests showed that the average makespan and RPI values of mIG are 1.93% and 78.35% better than the five comparison algorithms on average, respectively. Therefore, mIG is more suitable to solve the studied DBFSP_SDST.

Environmental concerns and economic constraints have led to increasing installations of mixed conductor circuits comprising underground cables (UGCs) and overhead transmission lines (OHLs). Faults on the OHL sections of such circuits are usually temporary, while there is a higher probability that faults on UGC sections are permanent. To maintain power system reliability and security, auto-reclose (AR) schemes are typically implemented to minimize outage duration after temporary OHL faults while blocking AR for UGC faults to prevent equipment damage. AR of a hybrid UCG–OHL transmission line, therefore, requires effective identification of the faulty section. However, the different electrical characteristics of UGC and OHL sections present significant challenges to existing protection and fault location methods. This paper presents a selective AR scheme for mixed conductor circuits based on the evaluation of differential currents in multiple defined protection zones, using distributed current transformer (CT) measurements provided by passive optical sensing. Case studies are conducted with a number of different UGC–OHL configurations, and the results demonstrate that the proposed scheme can accurately identify the faulty section, enabling effective selective AR of a comprehensive range of mixed conductor circuit topologies. The proposed scheme is also more cost effective, with reduced hardware requirements compared to conventional solutions. This paper thereby validates the optimal solution for mixed circuit protection as described in CIGRE Working Group B5.23 report 587.

This paper studies the hybrid flow shop scheduling problem with blocking constraints (BHFSP). To better understand the BHFSP, we will construct its mixed integer linear programming (MILP) model and use the Gurobi solver to demonstrate its correctness. Since the BHFSP exists parallel machines in some processing stages, different decoding strategies can obtain different makespan values for a given job sequence and multiple decoding strategies can assist the algorithm to find the optimal value. In view of this, we propose a hybrid decoding strategy that combines both forward decoding and backward decoding to select the minimal objective function value. In addition, a hybrid decoding-assisted variant iterated greedy (VIG) algorithm to solve the above MILP model. The main novelties of VIG are a new reconstruction mechanism based on the hybrid decoding strategy and a swap-based local reinforcement strategy, which can enrich the diversity of solutions and explore local neighborhoods more deeply. This evaluation is conducted against the VIG and six state-of-the-art algorithms from the literature. The 100 tests showed that the average makespan and the relative percentage increase (RPI) values of VIG are 1.00% and 89.6% better than the six comparison algorithms on average, respectively. Therefore, VIG is more suitable to solve the studied BHFSP.

Mixed-Fixed/Flex-Grid Optical Networks (MFGONs) are a new paradigm that emerged during the brown-field migration from fixed-grid Wavelength Division Multiplexing (WDM) optical networks to flex-grid Elastic Optical Networks (EONs). Based on the flex-grid, we can accommodate IP traffic directly to the optical layer by configuration. Considering the different granularities of spectrum resources and complex constraints in MFGONs, it is difficult to apply Routing and Wavelength/Spectrum Allocation (RWA/RSA) algorithms proposed in either fixed-grid or flex-grid optical networks. This paper first proposes two concepts, i.e., Link Spectrum Compactness (LSC) and Radiancy of Nodes (RoNs), to evaluate different scenarios of candidate paths for the end-to-end requests in MFGONs. Then, based on these two concepts, a Spectrum Entropy (SE) model is proposed in MFGONs. Here, the SE is the metric that combines LSC and RoNs to judge the fragmentation of network resources, and the value of SE is treated as the cost of candidate paths during the RSA operation. Finally, an SE-minimized RSA algorithm in MFGONs is designed. Simulation results prove that the proposed algorithm can effectively reduce the Bandwidth Blocking Ratio (BBR) and increase the revenues for upgrading the nodes compared to the state-of-the-art RSA algorithm. Particularly, the performance improvement is more obvious for highly connected networks.

Characterization of a deep circulation groundwater flow system is a big challenge, because the flow field and aqueous chemistry of deep circulation groundwater is significantly influenced by the geothermal reservoir. In this field study, we employed a geochemical approach to recognize a deep circulation groundwater pattern by combined the geochemistry analysis with isotopic measurements. The water samples were collected from the outlet of the Reshui River Basin which has a hot spring with a temperature of 88 °C. Experimental results reveal a fault-controlled deep circulation geothermal groundwater flow system. The weathering crust of the granitic mountains on the south of the basin collects precipitation infiltration, which is the recharge area of the deep circulation groundwater system. Water infiltrates from the land surface to a depth of about 3.8–4.3 km where the groundwater is heated up to around 170 °C in the geothermal reservoir. A regional active normal fault acts as a pathway of groundwater. The geothermal groundwater is then obstructed by a thrust fault and recharged by the hot spring, which is forced by the water pressure of convection derived from the 800 m altitude difference between the recharge and the discharge areas. Some part of groundwater flow within a geothermal reservoir is mixed with cold shallow groundwater. The isotopic fraction is positively correlated with the seasonal water table depth of shallow groundwater. Basic mineral dissolutions at thermoneutral conditions, hydrolysis with the aid of carbonic acid produced by the reaction of carbon dioxide with the water, and hydrothermal alteration in the geothermal reservoir add some extra chemical components into the geothermal water. The alkaline deep circulation groundwater is chemically featured by high contents of sodium, sulfate, chloride, fluorine, silicate, and some trace elements, such as lithium, strontium, cesium, and rubidium. Our results suggest that groundwater deep circulation convection exists in mountain regions where water-conducting fault and water-blocking fault combined properly. A significant elevation difference of topography is the other key.

It is known that it is critical for train rescheduling problem to address some uncertain disturbances to keep the normal condition of railway traffic. This paper is keen on a mathematical model to reschedule high-speed trains controlled by the quasi-moving blocking signalling system impacted by multidisturbances (i.e., primary delay, speed limitation, and siding line blockage). To be specific, a mixed-integer linear programming is formulated based on an improved alternative graph theory, by the means of rerouting, reordering, retiming, and train control. In order to adjust the train speed and find the best routes for trains, the set of alternative arcs and alternative arrival/departure paths are considered in the constraints, respectively. Due to this complex NP-hard problem, a two-step algorithm with three scheduling rules based on a commercial optimizer is applied to solve the problem efficiently in a real-word case, and the efficiency, validity, and feasibility of this method are demonstrated by a series of experimental tests. Finally, the graphical timetables rescheduled are analysed in terms of free conflicts of the solution. Consequently, the proposed mathematical model enriches the existing theory about train rescheduling, and it can also assist train dispatchers to figure out disturbances efficiently.

The debate over credit for Libya's shift away from “rogue state” policies, most especially by settling the Pan Am 103 Lockerbie terrorism case and abandoning its weapons of mass destruction (WMD) programs, is lively politically and challenging analytically. It has important implications for theories of force and diplomacy, particularly coercive diplomacy, and policy debates including such cases as Iran and North Korea. U.S. coercive diplomacy against Libya can be divided into three phases: the Reagan strategy of unilateral sanctions and military force, which largely failed; the mixed results from the more multilateral strategy of the George H.W. Bush and Bill Clinton administrations; and the substantial success achieved through the secret direct negotiations initiated along with Britain in the latter Clinton years and furthered under George W. Bush, which culminated in Libya closing down its WMD programs. These differences in success and failure are principally explained by (1) the extent of “balance” in the coercer state's strategy combining credible force and deft diplomacy consistent with three criteria—proportionality, reciprocity, and coercive credibility—taking into account international and domestic constraints; and (2) target state vulnerability as shaped by its domestic politics and economy, particularly whether domestic elites play a “circuit breaker” or “transmission belt” role in blocking or carrying forward external coercive pressure.

This study proposes Q-learning-based iterated greedy (IGQ) algorithms to solve the blocking flowshop scheduling problem with the makespan criterion. Q learning is a model-free machine intelligence technique, which is adapted into the traditional iterated greedy (IG) algorithm to determine its parameters, mainly, the destruction size and temperature scale factor, adaptively during the search process. Besides IGQ algorithms, two different mathematical modeling techniques. One of these techniques is the constraint programming (CP) model, which is known to work well with scheduling problems. The other technique is the mixed integer linear programming (MILP) model, which provides the mathematical definition of the problem. The introduction of these mathematical models supports the validation of IGQ algorithms and provides a comparison between different exact solution methodologies. To measure and compare the performance of IGQ algorithms and mathematical models, extensive computational experiments have been performed on both small and large VRF benchmarks available in the literature. Computational results and statistical analyses indicate that IGQ algorithms generate substantially better results when compared to non-learning IG algorithms.

The context in which a decision occurs can influence the decision-making process in many ways. In the laboratory, this is often evident in the effects of recent decisions. For instance, many experiments combine easy and difficult decisions, such as when word frequency is manipulated in lexical decision. The “blocking effect” describes how such decisions differ depending on whether the conditions are presented in pure blocks (comprised purely of easy or hard stimuli) or mixed blocks (also known as a “mixing cost”). We present a novel extension to these context effects, demonstrating in two experiments that they can be induced using conditions with identical difficulty, but different timing properties. This suggests that explanations of context effects based on task difficulty or error monitoring alone might be insufficient, and suggest a role for decision time. In prior work, we suggested such a hypothesis under the assumption that observers minimize their decision time, subject to an accuracy constraint. Consistent with this explanation, we find that decisions in slower conditions were based on less evidence when they were experienced in mixed compared to pure blocks.

Abstract. Well-resolved air–sea interactions are simulated in a new ocean mixed-layer, coupled configuration of the Met Office Unified Model (MetUM-GOML), comprising the MetUM coupled to the Multi-Column K Profile Parameterization ocean (MC-KPP). This is the first globally coupled system which provides a vertically resolved, high near-surface resolution ocean at comparable computational cost to running in atmosphere-only mode. As well as being computationally inexpensive, this modelling framework is adaptable – the independent MC-KPP columns can be applied selectively in space and time – and controllable – by using temperature and salinity corrections the model can be constrained to any ocean state. The framework provides a powerful research tool for process-based studies of the impact of air–sea interactions in the global climate system. MetUM simulations have been performed which separate the impact of introducing interannual variability in sea surface temperatures (SSTs) from the impact of having atmosphere–ocean feedbacks. The representation of key aspects of tropical and extratropical variability are used to assess the performance of these simulations. Coupling the MetUM to MC-KPP is shown, for example, to reduce tropical precipitation biases, improve the propagation of, and spectral power associated with, the Madden–Julian Oscillation and produce closer-to-observed patterns of springtime blocking activity over the Euro-Atlantic region.

Abstract. Well-resolved air–sea interactions are simulated in a new Ocean Mixed Layer coupled configuration of the Met Office Unified Model (MetUM-GOML), comprising the MetUM coupled to the Multi-Column K Profile Parametrization ocean (MC-KPP). This is the first globally coupled system which provides a vertically resolved, high near-surface resolution ocean at comparable computational cost to running in atmosphere-only mode. As well as being computationally inexpensive, this modelling framework is adaptable – the independent MC-KPP columns can be applied selectively in space and time – and controllable – by using temperature and salinity corrections the model can be constrained to any ocean state. The framework provides a powerful research tool for process-based studies of the impact of air–sea interactions in the global climate system. MetUM simulations have been performed which separate the impact of introducing interannual variability in sea surface temperatures (SSTs) from the impact of having atmosphere–ocean feedbacks. The representation of key aspects of tropical and extra-tropical variability are used to assess the performance of these simulations. Coupling the MetUM to MC-KPP is shown, for example, to reduce tropical precipitation biases, improve the propagation of, and spectral power associated with, the Madden–Julian Oscillation and produce closer-to-observed patterns of springtime blocking activity over the Euro-Atlantic region.

AbstractIn proposing a machine learning approach for a flow shop scheduling problem with alternative resources, sequence-dependent setup times, and blocking, this paper seeks to generate a tree-based priority rule in terms of a well-performing decision tree (DT) for dispatching jobs. Furthermore, generating a generic DT and RF that yields competitive results for instance scenarios that structurally differ from the training instances was another goal of our research. The proposed DT relies on high quality solutions, obtained using a constraint programming (CP) formulation. Novel aspects include a unified representation of job sequencing and machine assignment decisions, as well as the generation of random forests (RF) to counteract overfitting behaviour. To show the performance of the proposed approaches, different instance scenarios for two objectives (makespan and total tardiness minimisation) were implemented, based on randomised problem data. The background of this approach is a real-world physical system of an industrial partner that represents a typical shop floor for many production processes, such as furniture and window construction. The results of a comparison of the DT and RF approach with two priority dispatching rules, the original CP solutions and tight lower bounds retrieved from a strengthened mixed-integer programming (MIP) formulation show that the proposed machine learning approach performs well in most instance sets for the makespan objective and in all sets for the total tardiness objective.

This study revolved around the cognitive effects of online learning to health programs. It aimed to profile the respondents in terms of sex, program, devices used, and residence; to determine the respondents’ perceptions on the cognitive effects of online learning along entailing memory, critical thinking, comprehension and decision making; to discover the challenges encountered by the students in online learning; to know the significant difference of the responses when grouped according to profile variables and to present recommendations based from the findings. This research made use of the mixed methods design involving descriptive and comparative methods. The study was conducted for four months with 96 health programs respondents. The data were gathered through Google Forms. This study found that the majority of the respondents were female, enrolled in BS nursing, using both laptops and smartphones and are located in Nueva Vizcaya. The cognitive effects in terms of memory, critical thinking, and decision making were sometimes exhibited while effects along comprehension were usually demonstrated. Furthermore, the most prevalent challenges encountered by the students in online learning are environmental distractions and time constraint. There were no significant differences of the responses on the cognitive effects of the respondents when grouped according to the profile variables. The recommendations forwarded were using of app blocking applications, online information restricting platforms, evaluation of motivating factors and social support. The researchers recommend adding other socio-economic variables, increasing sample size, providing teachers with online-learning-related trainings and submitting coping strategies for review by authorities.

In container terminals equipped with shuttle vehicles, apron buffer zones are necessary for linking up the operations of quay cranes and shuttle vehicles. An integrated quay crane - shuttle vehicle scheduling problem with limited apron buffer capacity is investigated in this paper. This problem is subject to the practical constraints on nonzero traveling time, precedence relationships between container handling jobs, quay crane non-interference, safety margin, blocking, and apron buffer capacity constraint. The objective of this investigation is to minimize the makespan of vessel handling by simultaneous optimization of bay-to-quay crane assignment, the sequences of bays handled by quay cranes, the sequences of jobs handled by quay cranes, job-to-shuttle vehicle assignment and the sequences of jobs handled by shuttle vehicles. To achieve this, a mixed-integer linear programming model is first formulated to solve the scheduling problem. Second, the relationships of decision variables and model constraints are discussed to generate two sub-models: assignment-based and sequence-based. The assignment-based sub-model is developed from the proposed model by pre-determining the assignment of bay-to-quay cranes and job-to-shuttle vehicles, and the other is developed from the proposed model by pre-determining the sequences of jobs handled by each QC and each SV. Third, the hybrid genetic algorithms with the two sub-models are proposed. Fourth, numerical experiments show that the algorithms are competitive, compared to on-the-shelf solvers. Finally, practical implications of this investigation for apron buffer zone design are discussed.

Abstract Background The concept of minimal cut sets (MCS) has become an important mathematical framework for analyzing and (re)designing metabolic networks. However, the calculation of MCS in genome-scale metabolic models is a complex computational problem. The development of duality-based algorithms in the last years allowed the enumeration of thousands of MCS in genome-scale networks by solving mixed-integer linear problems (MILP). A recent advancement in this field was the introduction of the MCS2 approach. In contrast to the Farkas-lemma-based dual system used in earlier studies, the MCS2 approach employs a more condensed representation of the dual system based on the nullspace of the stoichiometric matrix, which, due to its reduced dimension, holds promise to further enhance MCS computations. Results In this work, we introduce several new variants and modifications of duality-based MCS algorithms and benchmark their effects on the overall performance. As one major result, we generalize the original MCS2 approach (which was limited to blocking the operation of certain target reactions) to the most general case of MCS computations with arbitrary target and desired regions. Building upon these developments, we introduce a new MILP variant which allows maximal flexibility in the formulation of MCS problems and fully leverages the reduced size of the nullspace-based dual system. With a comprehensive set of benchmarks, we show that the MILP with the nullspace-based dual system outperforms the MILP with the Farkas-lemma-based dual system speeding up MCS computation with an averaged factor of approximately 2.5. We furthermore present several simplifications in the formulation of constraints, mainly related to binary variables, which further enhance the performance of MCS-related MILP. However, the benchmarks also reveal that some highly condensed formulations of constraints, especially on reversible reactions, may lead to worse behavior when compared to variants with a larger number of (more explicit) constraints and involved variables. Conclusions Our results further enhance the algorithmic toolbox for MCS calculations and are of general importance for theoretical developments as well as for practical applications of the MCS framework.

SummaryIn this paper, we propose a reactive defragmentation with minimum spectrum route (RDMSR) for the problem of route, spectrum, and modulation‐format allocation (RSMA) in mixed grid optical network. In mixed grid network, spectrum redundancy and its assignment problem increase due to the spectrum continuity and contiguity constrains. In the proposed RDMSR strategy, process of defragmentation initiates after the termination of the existing connections. In addition, the route that needs minimum spectrum is given priority over the other available routes. The performance of the proposed strategy is compared with the two existing strategies: shortest path first (SPF) and mixed grid aware dynamic resources allocation (MDRA). Simulations are performed on NSFNET and ARPANET topologies. The existing and proposed strategies are evaluated on the metrics of bandwidth blocking probability (BBP), network capacity (NC), and average hops (AH) at three different combinations of the network traffic. Results show the proposed strategy outperforms than the other existing state of art strategies.

Background: Out-of-hospital cardiac arrest (OHCA) patients are at high risk of morbidity and mortality attributable to the post-cardiac arrest syndrome, in which systemic inflammation is a major component. Cytokines are involved in many processes, including inflammation. In the IMICA trial, treatment with the interleukin 6 receptor (IL-6R) antagonist tocilizumab in resuscitated comatose OHCA patients reduced systemic inflammation as characterized by a greatly reduced CRP response and lower levels of leukocytes as compared to placebo. Markers of myocardial injury were also reduced by treatment. Aim: To investigate changes in cytokine levels induced by blocking the IL-6-mediated signaling with tocilizumab after OHCA by employing a broad cytokine panel. Methods: We randomized 80 patients to a single infusion of tocilizumab 8 mg/kg or placebo after admission. Blood samples were drawn at 0, 24, 48, and 72 hours. Cytokines were measured using a 17-plex cytokine assay: G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1β, TNF-α, IL- 1β, 2, 4-8, 10, 12, 13, and 17. Data were log2 transformed and analyzed by constrained linear mixed models. Results: Most cytokines had temporal changes after OHCA. However, only for IL- 5, 6 (Figure) and 17 were the treatment-by-time interactions significant, all p<0.05. Circulating IL-5 and in particular IL-6 was markedly increased by inhibition of the IL-6R with tocilizumab as compared to the placebo group. For IL-17 the changes were less pronounced and only differed between groups at 72 hours. Conclusions: Treatment with the IL-6R antagonist, tocilizumab, did not alter the cytokine responses in general, however, IL-5 and IL-6 were markedly increased. Experimental data suggests that IL-5 may play a role in cardiac recovery after ischemia. Blockage of the IL-6R greatly increased the IL-6 levels, and as the CRP response was greatly reduced by tocilizumab, a response strongly associated with IL-6, it can be demonstrated that the function of IL-6 was blunted.

Introduction I think the Privacy Act is a huge edifice to protect the minority of things that could go wrong. I’ve got a good example for you, I’m just trying to think … yeah the worst one I’ve ever seen was the Balga Youth Program where we took these students on a reward excursion all the way to Fremantle and suddenly this very alienated kid started to jump under a bus, a moving bus so the kid had to be restrained. The cops from Fremantle arrived because all the very good people in Fremantle were alarmed at these grown-ups manhandling a kid and what had happened is that DCD [Department of Community Development] had dropped him into the program but hadn’t told us that this kid had suicide tendencies. No, it’s just chronically bad. And there were caseworkers involved and … there is some information that we have to have that doesn’t get handed down. Rather than a blanket rule that everything’s confidential coming from them to us, and that was a real live situation, and you imagine how we’re trying to handle it, we had taxis going from Balga to Fremantle to get staff involved and we only had to know what to watch out for and we probably could have … well what you would have done is not gone on the excursion I suppose (School Principal, quoted in Balnaves and Luca 49). These comments are from a school principal in Perth, Western Australia in a school that is concerned with “at-risk” students, and in a context where the Commonwealth Privacy Act 1988 has imposed limitations on their work. Under this Act it is illegal to pass health, personal or sensitive information concerning an individual on to other people. In the story cited above the Department of Community Development personnel were apparently protecting the student’s “negative right”, that is, “freedom from” interference by others. On the other hand, the principal’s assertion that such information should be shared is potentially a “positive right” because it could cause something to be done in that person’s or society’s interests. Balnaves and Luca noted that positive and negative rights have complex philosophical underpinnings, and they inform much of how we operate in everyday life and of the dilemmas that arise (49). For example, a ban on euthanasia or the “assisted suicide” of a terminally ill person can be a “positive right” because it is considered to be in the best interests of society in general. However, physicians who tacitly approve a patient’s right to end their lives with a lethal dose by legally prescribed dose of medication could be perceived as protecting the patient’s “negative right” as a “freedom from” interference by others. While acknowledging the merits of collaboration between people who are working to improve the wellbeing of students “at-risk”, this paper examines some of the barriers to collaboration. Based on both primary and secondary sources, and particularly on oral testimonies, the paper highlights the tension between privacy as a negative right and collaborative helping as a positive right. It also points to other difficulties and dilemmas within and between the institutions engaged in this joint undertaking. The authors acknowledge Michel Foucault’s contention that discourse is power. The discourse on privacy and the sharing of information in modern societies suggests that privacy is a negative right that gives freedom from bureaucratic interference and protects the individual. However, arguably, collaboration between agencies that are working to support individuals “at-risk” requires a measured relaxation of the requirements of this negative right. Children and young people “at-risk” are a case in point. Towards Collaboration From a series of interviews conducted in 2004, the school authorities at Balga Senior High School and Midvale Primary School, people working for the Western Australian departments of Community Development, Justice, and Education and Training in Western Australia, and academics at the Edith Cowan and Curtin universities, who are working to improve the wellbeing of students “at-risk” as part of an Australian Research Council (ARC) project called Smart Communities, have identified students “at-risk” as individuals who have behavioural problems and little motivation, who are alienated and possibly violent or angry, who under-perform in the classroom and have begun to truant. They noted also that students “at-risk” often suffer from poor health, lack of food and medication, are victims of unwanted pregnancies, and are engaged in antisocial and illegal behaviour such as stealing cars and substance abuse. These students are also often subject to domestic violence (parents on drugs or alcohol), family separation, and homelessness. Some are depressed or suicidal. Sometimes cultural factors contribute to students being regarded as “at-risk”. For example, a social worker in the Smart Communities project stated: Cultural factors sometimes come into that as well … like with some Muslim families … they can flog their daughter or their son, usually the daughter … so cultural factors can create a risk. Research elsewhere has revealed that those children between the ages of 11-17 who have been subjected to bullying at school or physical or sexual abuse at home and who have threatened and/or harmed another person or suicidal are “high-risk” youths (Farmer 4). In an attempt to bring about a positive change in these alienated or “at-risk” adolescents, Balga Senior High School has developed several programs such as the Youth Parents Program, Swan Nyunger Sports Education program, Intensive English Centre, and lower secondary mainstream program. The Midvale Primary School has provided services such as counsellors, Aboriginal child protection workers, and Aboriginal police liaison officers for these “at-risk” students. On the other hand, the Department of Community Development (DCD) has provided services to parents and caregivers for children up to 18 years. Academics from Edith Cowan and Curtin universities are engaged in gathering the life stories of these “at-risk” students. One aspect of this research entails the students writing their life stories in a secured web portal that the universities have developed. The researchers believe that by engaging the students in these self-exploration activities, they (the students) would develop a more hopeful outlook on life. Though all agencies and educational institutions involved in this collaborative project are working for the well-being of the children “at-risk”, the Privacy Act forbids the authorities from sharing information about them. A school psychologist expressed concern over the Privacy Act: When the Juvenile Justice Department want to reintroduce a student into a school, we can’t find out anything about this student so we can’t do any preplanning. They want to give the student a fresh start, so there’s always that tension … eventually everyone overcomes [this] because you realise that the student has to come to the school and has to be engaged. Of course, the manner and consequences of a student’s engagement in school cannot be predicted. In the scenario described above students may have been given a fair chance to reform themselves, which is their positive right but if they turn out to be at “high risk” it would appear that the Juvenile Department protected the negative right of the students by supporting “freedom from” interference by others. Likewise, a school health nurse in the project considered confidentiality or the Privacy Act an important factor in the security of the student “at-risk”: I was trying to think about this kid who’s one of the children who has been sexually abused, who’s a client of DCD, and I guess if police got involved there and wanted to know details and DCD didn’t want to give that information out then I’d guess I’d say to the police “Well no, you’ll have to talk to the parents about getting further information.” I guess that way, recognising these students are minor and that they are very vulnerable, their information … where it’s going, where is it leading? Who wants to know? Where will it be stored? What will be the outcomes in the future for this kid? As a 14 year old, if they’re reckless and get into things, you know, do they get a black record against them by the time they’re 19? What will that information be used for if it’s disclosed? So I guess I become an advocate for the student in that way? Thus the nurse considers a sexually abused child should not be identified. It is a positive right in the interest of the person. Once again, though, if the student turns out to be at “high risk” or suicidal, then it would appear that the nurse was protecting the youth’s negative right—“freedom from” interference by others. Since collaboration is a positive right and aims at the students’ welfare, the workable solution to prevent the students from suicide would be to develop inter-agency trust and to share vital information about “high-risk” students. Dilemmas of Collaboration Some recent cases of the deaths of young non-Caucasian girls in Western countries, either because of the implications of the Privacy Act or due to a lack of efficient and effective communication and coordination amongst agencies, have raised debates on effective child protection. For example, the British Laming report (2003) found that Victoria Climbié, a young African girl, was sent by her parents to her aunt in Britain in order to obtain a good education and was murdered by her aunt and aunt’s boyfriend. However, the risk that she could be harmed was widely known. The girl’s problems were known to 6 local authorities, 3 housing authorities, 4 social services, 2 child protection teams, and the police, the local church, and the hospital, but not to the education authorities. According to the Laming Report, her death could have been prevented if there had been inter-agency sharing of information and appropriate evaluation (Balnaves and Luca 49). The agencies had supported the negative rights of the young girl’s “freedom from” interference by others, but at the cost of her life. Perhaps Victoria’s racial background may have contributed to the concealment of information and added to her disadvantaged position. Similarly, in Western Australia, the Gordon Inquiry into the death of Susan Taylor, a 15 year old girl Aboriginal girl at the Swan Nyungah Community, found that in her short life this girl had encountered sexual violation, violence, and the ravages of alcohol and substance abuse. The Gordon Inquiry reported: Although up to thirteen different agencies were involved in providing services to Susan Taylor and her family, the D[epartment] of C[ommunity] D[evelopment] stated they were unaware of “all the services being provided by each agency” and there was a lack of clarity as to a “lead coordinating agency” (Gordon et al. quoted in Scott 45). In this case too, multiple factors—domestic, racial, and the Privacy Act—may have led to Susan Taylor’s tragic end. In the United Kingdom, Harry Ferguson noted that when a child is reported to be “at-risk” from domestic incidents, they can suffer further harm because of their family’s concealment (204). Ferguson’s study showed that in 11 per cent of the 319 case sample, children were known to be re-harmed within a year of initial referral. Sometimes, the parents apply a veil of secrecy around themselves and their children by resisting or avoiding services. In such cases the collaborative efforts of the agencies and education may be thwarted. Lack of cultural education among teachers, youth workers, and agencies could also put the “at-risk” cultural minorities into a high risk category. For example, an “at-risk” Muslim student may not be willing to share personal experiences with the school or agencies because of religious sensitivities. This happened in the UK when Khadji Rouf was abused by her father, a Bangladeshi. Rouf’s mother, a white woman, and her female cousin from Bangladesh, both supported Rouf when she finally disclosed that she had been sexually abused for over eight years. After group therapy, Rouf stated that she was able to accept her identity and to call herself proudly “mixed race”, whereas she rejected the Asian part of herself because it represented her father. Other Asian girls and young women in this study reported that they could not disclose their abuse to white teachers or social workers because of the feeling that they would be “letting down their race or their Muslim culture” (Rouf 113). The marginalisation of many Muslim Australians both in the job market and in society is long standing. For example, in 1996 and again in 2001 the Muslim unemployment rate was three times higher than the national total (Australian Bureau of Statistics). But since the 9/11 tragedy and Bali bombings visible Muslims, such as women wearing hijabs (headscarves), have sometimes been verbally and physically abused and called ‘terrorists’ by some members of the wider community (Dreher 13). The Howard government’s new anti-terrorism legislation and the surveillance hotline ‘Be alert not alarmed’ has further marginalised some Muslims. Some politicians have also linked Muslim asylum seekers with terrorists (Kabir 303), which inevitably has led Muslim “at-risk” refugee students to withdraw from school support such as counselling. Under these circumstances, Muslim “at-risk” students and their parents may prefer to maintain a low profile rather than engage with agencies. In this case, arguably, federal government politics have exacerbated the barriers to collaboration. It appears that unfamiliarity with Muslim culture is not confined to mainstream Australians. For example, an Aboriginal liaison police officer engaged in the Smart Communities project in Western Australia had this to say about Muslim youths “at-risk”: Different laws and stuff from different countries and they’re coming in and sort of thinking that they can bring their own laws and religions and stuff … and when I say religions there’s laws within their religions as well that they don’t seem to understand that with Australia and our laws. Such generalised misperceptions of Muslim youths “at-risk” would further alienate them, thus causing a major hindrance to collaboration. The “at-risk” factors associated with Aboriginal youths have historical connections. Research findings have revealed that indigenous youths aged between 10-16 years constitute a vast majority in all Australian States’ juvenile detention centres. This over-representation is widely recognised as associated with the nature of European colonisation, and is inter-related with poverty, marginalisation and racial discrimination (Watson et al. 404). Like the Muslims, their unemployment rate was three times higher than the national total in 2001 (ABS). However, in 1998 it was estimated that suicide rates among Indigenous peoples were at least 40 per cent higher than national average (National Advisory Council for Youth Suicide Prevention, quoted in Elliot-Farrelly 2). Although the wider community’s unemployment rate is much lower than the Aboriginals and the Muslims, the “at-risk” factors of mainstream Australian youths are often associated with dysfunctional families, high conflict, low-cohesive families, high levels of harsh parental discipline, high levels of victimisation by peers, and high behavioural inhibition (Watson et al. 404). The Macquarie Fields riots in 2005 revealed the existence of “White” underclass and “at-risk” people in Sydney. Macquarie Fields’ unemployment rate was more than twice the national average. Children growing up in this suburb are at greater risk of being involved in crime (The Age). Thus small pockets of mainstream underclass youngsters also require collaborative attention. In Western Australia people working on the Smart Communities project identified that lack of resources can be a hindrance to collaboration for all sectors. As one social worker commented: “government agencies are hierarchical systems and lack resources”. They went on to say that in their department they can not give “at-risk” youngsters financial assistance in times of crisis: We had a petty cash box which has got about 40 bucks in it and sometimes in an emergency we might give a customer a couple of dollars but that’s all we can do, we can’t give them any larger amount. We have bus/metro rail passes, that’s the only thing that we’ve actually got. A youth worker in Smart Communities commented that a lot of uncertainty is involved with young people “at-risk”. They said that there are only a few paid workers in their field who are supported and assisted by “a pool of volunteers”. Because the latter give their time voluntarily they are under no obligation to be constant in their attendance, so the number of available helpers can easily fluctuate. Another youth worker identified a particularly important barrier to collaboration: because of workers’ relatively low remuneration and high levels of work stress, the turnover rates are high. The consequence of this is as follows: The other barrier from my point is that you’re talking to somebody about a student “at-risk”, and within 14 months or 18 months a new person comes in [to that position] then you’ve got to start again. This way you miss a lot of information [which could be beneficial for the youth]. Conclusion The Privacy Act creates a dilemma in that it can be either beneficial or counter-productive for a student’s security. To be blunt, a youth who has suicided might have had their privacy protected, but not their life. Lack of funding can also be a constraint on collaboration by undermining stability and autonomy in the workforce, and blocking inter-agency initiatives. Lack of awareness about cultural differences can also affect unity of action. The deepening inequality between the “haves” and “have-nots” in the Australian society, and the Howard government’s harshness on national security issues, can also pose barriers to collaboration on youth issues. Despite these exigencies and dilemmas, it would seem that collaboration is “the only game” when it comes to helping students “at-risk”. To enhance this collaboration, there needs to be a sensible modification of legal restrictions to information sharing, an increase in government funding and support for inter-agency cooperation and informal information sharing, and an increased awareness about the cultural needs of minority groups and knowledge of the mainstream underclass. Acknowledgments The research is part of a major Australian Research Council (ARC) funded project, Smart Communities. The authors very gratefully acknowledge the contribution of the interviewees, and thank *Donald E. Scott for conducting the interviews. References Australian Bureau of Statistics. 1996 and 2001. 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"Students “at Risk”: Dilemmas of Collaboration." M/C Journal 9.2 (2006). echo date('d M. Y'); ?> <http://journal.media-culture.org.au/0605/04-kabirbalnaves.php>. APA Style Kabir, N., and M. Balnaves. (May 2006) "Students “at Risk”: Dilemmas of Collaboration," M/C Journal, 9(2). Retrieved echo date('d M. Y'); ?> from <http://journal.media-culture.org.au/0605/04-kabirbalnaves.php>.