Ilham ilhams - Academia.edu (original) (raw)

Papers by Ilham ilhams

Computers & Operations Research, 2006

The field of dynamic vehicle routing and scheduling is growing at a fast pace nowadays, due to ma... more The field of dynamic vehicle routing and scheduling is growing at a fast pace nowadays, due to many potential applications in courier services, emergency services, truckload and less-than-truckload trucking, and many others. In this paper, a dynamic vehicle routing and scheduling problem with time windows is described where both real-time customer requests and dynamic travel times are considered. Different reactive dispatching strategies are defined and compared through the setting of a single "tolerance" parameter. The results show that some tolerance to deviations with the current planned solution usually leads to better solutions.

IEEE Transactions on Systems, Man, and Cybernetics, 1998

Vehicle dispatching consists of allocating real-time service requests to a fleet of moving vehicl... more Vehicle dispatching consists of allocating real-time service requests to a fleet of moving vehicles. In this paper, each vehicle is associated with a vector of attribute values that describes its current situation with respect to new incoming service requests. Using this attribute description, a utility function aimed at approximating the decision process of a professional dispatcher is constructed through genetic programming. Computational results are reported on requests collected from a courier service company and a comparison is provided with a neural network model and a simple dispatching policy.

Proceedings of The National Academy of Sciences, 2000

Heat shock protein (hsp)90 functions in a complex chaperoning pathway where its activity is modul... more Heat shock protein (hsp)90 functions in a complex chaperoning pathway where its activity is modulated by ATP and by interaction with several co-chaperones. One co-chaperone, p23, binds selectively to the ATP-bound state of hsp90. However, the isolated ATP-binding domain of hsp90 does not bind p23. In an effort to identify the p23-binding domain, we have constructed a series of hsp90 deletion mutants fused with glutathione-S-transferase (GST). Full-length GST-hsp90 is able to bind p23, and also, to chaperone assembly of progesterone receptor complexes. Truncations from the C terminus of GST-hsp90 reveal a C-terminal boundary for the p23-binding domain at approximately residue 490. This fragment contains, in order, the ATP-binding domain, a highly charged region, and 203 residues beyond the charged region. p23 binding is unaffected by deletion of the charged region, indicating that two noncontiguous regions of hsp90 are involved in p23 binding. These regions are only effective when hsp90 is in a dimeric state as shown by loss of p23 binding upon removal of GST or as shown by use of FK506-binding protein12-hsp90 constructs that form dimers and bind p23 only in the presence of a bivalent drug. Thus, p23 binding requires an hsp90 dimer with close proximity between N-terminal regions of hsp90 and a conformation specified by ATP.

Journal of Pineal Research, 1998

ABSTRACT: In this paper, we summarize the results of in vitro studies showing that physiological ... more ABSTRACT: In this paper, we summarize the results of in vitro studies showing that physiological concentrations of melatonin inhibit the norepinephrine-induced activation of prostaglandin E2 (PGE2) and cyclic AMP production in rat medial basal hypothalamus (MBH). Interestingly, a concentration of melatonin as low as 1 nM, which is roughly equivalent to the nocturnal serum physiological concentration of the hormone in the rat, significantly inhibit PGE2 and cyclic AMP production in the MBH. The suppressive effect of melatonin may be mediated by an inhibition of nitric oxide synthase (NOS) activity, since the stimulatory effect of sodium nitroprusside (SNP), a spontaneous generator of NO, was not prevented by melatonin. Melatonin also inhibited NOS activity in rat MBH in a dose-dependent manner. The results suggest the existence of a new or an ancillary means by which melatonin may regulate the physiology of the hypothalamus-pituitary unit.

This work deals with the problem of target tracking in wireless sensor networks where the observe... more This work deals with the problem of target tracking in wireless sensor networks where the observed system is assumed to evolve according to a probabilistic state space model. We propose to improve the use of the variational filtering (VF) by quantizing the data collected by the sensors to higher levels respecting the tradeoff between the information relevance of sensor measurements and the energy costs. In fact, VF has been shown to be suitable to the communication constraints of sensor networks. Its efficiency relies on the fact that the online update of the filtering distribution and its compression are simultaneously performed. But till now, it has been used only for binary sensor networks. In this paper, we propose an adaptive quantization algorithm taking benefit from the VF properties. At each sampling instant, by minimizing the Crameacuter-Rao bound, the adaptive quantization technique provides the optimal number of quantization bits per observation. The computation of this criteria is based on the target position predictive distribution provided by the VF algorithm. The simulation results show that the adaptive quantization algorithm, for the same sensor transmitting power, outperforms both the VF algorithm using a fixed optimal quantization level (minimizing the MSE) and the VF algorithm based on binary sensors.

Alcoholism-clinical and Experimental Research, 2001

Background: The role of the δ-opioid receptor in ethanol drinking has remained unclear despite th... more Background: The role of the δ-opioid receptor in ethanol drinking has remained unclear despite the use of traditional pharmacological and correlational approaches. The results of several studies suggest that pharmacological blockade of these receptors results in decreases in ethanol drinking behavior, but an approximately equal number of reports have failed to observe an effect of δ-receptor antagonism on ethanol drinking. It is clear that alternative approaches to understanding opioid-receptor involvement in ethanol drinking are needed.Methods: In this study, ethanol drinking was examined in δ-opioid receptor knockout (KO) mice by using first a two-bottle–choice test, then an operant self-administration paradigm and a second two-bottle–choice test, in that order. In addition, because KO mice were previously shown to display enhanced anxiety-like behavior relative to wild-type (WT) mice, the effect of ethanol self-administration on anxiety-like responses was determined.Results: δ KO mice initially showed no evidence of a preference for ethanol in the first two-bottle–choice drinking test; however, after an experience of operant self-administration of ethanol, a preference for ethanol developed in the second two-bottle–choice test. KO mice also showed a preference for ethanol over water and self-administered more ethanol than WT mice in the operant self-administration paradigm. The ethanol self-administered in this procedure was sufficient to reverse the innate anxiety-like response observed in this strain.Conclusions: δ KO mice showed a greater preference for ethanol and consumed more ethanol than their WT counterparts, suggesting that a decrease in δ-receptor activity is associated with increased ethanol-drinking behavior. It is hypothesized that δ receptors may influence ethanol self-administration at least partly through an effect of these receptors on anxiety-like behavior.

American Journal of Infection Control, 1999

Biosensors & Bioelectronics, 2006

Analytical technology based on sensors is an extremely broad field which impacts on many major in... more Analytical technology based on sensors is an extremely broad field which impacts on many major industrial sectors such as the pharmaceutical, healthcare, food, and agriculture industries as well as environmental monitoring. This review will highlight the research carried out during the last 5 years on biosensors that are based on enzyme inhibition for determination of pollutants and toxic compounds in a wide range of samples. Here the different enzymes implicated in the inhibition, different transducers forming the sensing devices, and the different contaminants analyzed are considered.

The pygmy rabbit (Brachylagus idahoensis), a leporid of the Great Basin and southern Wyoming, res... more The pygmy rabbit (Brachylagus idahoensis), a leporid of the Great Basin and southern Wyoming, resides in habitats dominated by big sagebrush (Artemisia tridentata). Because of the patchy distribution of mature big sagebrush in southern Wyoming, we expected pygmy rabbits to exhibit genetic attributes associated with genetic isolation: high levels of spatially structured differentiation. We also predicted some reduction in genetic diversity in the peninsular Wyoming portion of the geographic range, relative to its Great Basin core. We used 14 microsatellite loci to compare genetic attributes between geographically distinct pygmy rabbit populations, and a subset of these microsatellite loci to compare with those of 2 sympatric cottontails (Sylvilagus spp.), both presumptive habitat generalists. Pygmy rabbits displayed moderate genetic diversity that was lower than that reported from locations near the core of the geographic range (Idaho and Montana). We observed only low levels of genetic differentiation in pygmy rabbits among sampling sites within Wyoming. Similarly, we observed low levels of differentiation in one species of cottontail sympatric with pygmy rabbits; however, the other species of sympatric cottontail displayed levels of differentiation congruent with those of populations at panmixia. Isolation-by-distance was the dominant genetic pattern observed, although examination of our data suggested that a 4-lane highway (Interstate 80) might affect gene flow measurably. In the recent evolutionary past, habitat connectivity and dispersal capacity for pygmy rabbits have been high enough to maintain gene flow among sites across southern Wyoming. Conservation of the species should focus on maintaining the connectivity among preferred habitats: old stands of big sagebrush.

Computers & Operations Research, 2006

The field of dynamic vehicle routing and scheduling is growing at a fast pace nowadays, due to ma... more The field of dynamic vehicle routing and scheduling is growing at a fast pace nowadays, due to many potential applications in courier services, emergency services, truckload and less-than-truckload trucking, and many others. In this paper, a dynamic vehicle routing and scheduling problem with time windows is described where both real-time customer requests and dynamic travel times are considered. Different reactive dispatching strategies are defined and compared through the setting of a single "tolerance" parameter. The results show that some tolerance to deviations with the current planned solution usually leads to better solutions.

IEEE Transactions on Systems, Man, and Cybernetics, 1998

Vehicle dispatching consists of allocating real-time service requests to a fleet of moving vehicl... more Vehicle dispatching consists of allocating real-time service requests to a fleet of moving vehicles. In this paper, each vehicle is associated with a vector of attribute values that describes its current situation with respect to new incoming service requests. Using this attribute description, a utility function aimed at approximating the decision process of a professional dispatcher is constructed through genetic programming. Computational results are reported on requests collected from a courier service company and a comparison is provided with a neural network model and a simple dispatching policy.

Proceedings of The National Academy of Sciences, 2000

Heat shock protein (hsp)90 functions in a complex chaperoning pathway where its activity is modul... more Heat shock protein (hsp)90 functions in a complex chaperoning pathway where its activity is modulated by ATP and by interaction with several co-chaperones. One co-chaperone, p23, binds selectively to the ATP-bound state of hsp90. However, the isolated ATP-binding domain of hsp90 does not bind p23. In an effort to identify the p23-binding domain, we have constructed a series of hsp90 deletion mutants fused with glutathione-S-transferase (GST). Full-length GST-hsp90 is able to bind p23, and also, to chaperone assembly of progesterone receptor complexes. Truncations from the C terminus of GST-hsp90 reveal a C-terminal boundary for the p23-binding domain at approximately residue 490. This fragment contains, in order, the ATP-binding domain, a highly charged region, and 203 residues beyond the charged region. p23 binding is unaffected by deletion of the charged region, indicating that two noncontiguous regions of hsp90 are involved in p23 binding. These regions are only effective when hsp90 is in a dimeric state as shown by loss of p23 binding upon removal of GST or as shown by use of FK506-binding protein12-hsp90 constructs that form dimers and bind p23 only in the presence of a bivalent drug. Thus, p23 binding requires an hsp90 dimer with close proximity between N-terminal regions of hsp90 and a conformation specified by ATP.

Journal of Pineal Research, 1998

ABSTRACT: In this paper, we summarize the results of in vitro studies showing that physiological ... more ABSTRACT: In this paper, we summarize the results of in vitro studies showing that physiological concentrations of melatonin inhibit the norepinephrine-induced activation of prostaglandin E2 (PGE2) and cyclic AMP production in rat medial basal hypothalamus (MBH). Interestingly, a concentration of melatonin as low as 1 nM, which is roughly equivalent to the nocturnal serum physiological concentration of the hormone in the rat, significantly inhibit PGE2 and cyclic AMP production in the MBH. The suppressive effect of melatonin may be mediated by an inhibition of nitric oxide synthase (NOS) activity, since the stimulatory effect of sodium nitroprusside (SNP), a spontaneous generator of NO, was not prevented by melatonin. Melatonin also inhibited NOS activity in rat MBH in a dose-dependent manner. The results suggest the existence of a new or an ancillary means by which melatonin may regulate the physiology of the hypothalamus-pituitary unit.

This work deals with the problem of target tracking in wireless sensor networks where the observe... more This work deals with the problem of target tracking in wireless sensor networks where the observed system is assumed to evolve according to a probabilistic state space model. We propose to improve the use of the variational filtering (VF) by quantizing the data collected by the sensors to higher levels respecting the tradeoff between the information relevance of sensor measurements and the energy costs. In fact, VF has been shown to be suitable to the communication constraints of sensor networks. Its efficiency relies on the fact that the online update of the filtering distribution and its compression are simultaneously performed. But till now, it has been used only for binary sensor networks. In this paper, we propose an adaptive quantization algorithm taking benefit from the VF properties. At each sampling instant, by minimizing the Crameacuter-Rao bound, the adaptive quantization technique provides the optimal number of quantization bits per observation. The computation of this criteria is based on the target position predictive distribution provided by the VF algorithm. The simulation results show that the adaptive quantization algorithm, for the same sensor transmitting power, outperforms both the VF algorithm using a fixed optimal quantization level (minimizing the MSE) and the VF algorithm based on binary sensors.

Alcoholism-clinical and Experimental Research, 2001

Background: The role of the δ-opioid receptor in ethanol drinking has remained unclear despite th... more Background: The role of the δ-opioid receptor in ethanol drinking has remained unclear despite the use of traditional pharmacological and correlational approaches. The results of several studies suggest that pharmacological blockade of these receptors results in decreases in ethanol drinking behavior, but an approximately equal number of reports have failed to observe an effect of δ-receptor antagonism on ethanol drinking. It is clear that alternative approaches to understanding opioid-receptor involvement in ethanol drinking are needed.Methods: In this study, ethanol drinking was examined in δ-opioid receptor knockout (KO) mice by using first a two-bottle–choice test, then an operant self-administration paradigm and a second two-bottle–choice test, in that order. In addition, because KO mice were previously shown to display enhanced anxiety-like behavior relative to wild-type (WT) mice, the effect of ethanol self-administration on anxiety-like responses was determined.Results: δ KO mice initially showed no evidence of a preference for ethanol in the first two-bottle–choice drinking test; however, after an experience of operant self-administration of ethanol, a preference for ethanol developed in the second two-bottle–choice test. KO mice also showed a preference for ethanol over water and self-administered more ethanol than WT mice in the operant self-administration paradigm. The ethanol self-administered in this procedure was sufficient to reverse the innate anxiety-like response observed in this strain.Conclusions: δ KO mice showed a greater preference for ethanol and consumed more ethanol than their WT counterparts, suggesting that a decrease in δ-receptor activity is associated with increased ethanol-drinking behavior. It is hypothesized that δ receptors may influence ethanol self-administration at least partly through an effect of these receptors on anxiety-like behavior.

American Journal of Infection Control, 1999

Biosensors & Bioelectronics, 2006

Analytical technology based on sensors is an extremely broad field which impacts on many major in... more Analytical technology based on sensors is an extremely broad field which impacts on many major industrial sectors such as the pharmaceutical, healthcare, food, and agriculture industries as well as environmental monitoring. This review will highlight the research carried out during the last 5 years on biosensors that are based on enzyme inhibition for determination of pollutants and toxic compounds in a wide range of samples. Here the different enzymes implicated in the inhibition, different transducers forming the sensing devices, and the different contaminants analyzed are considered.

The pygmy rabbit (Brachylagus idahoensis), a leporid of the Great Basin and southern Wyoming, res... more The pygmy rabbit (Brachylagus idahoensis), a leporid of the Great Basin and southern Wyoming, resides in habitats dominated by big sagebrush (Artemisia tridentata). Because of the patchy distribution of mature big sagebrush in southern Wyoming, we expected pygmy rabbits to exhibit genetic attributes associated with genetic isolation: high levels of spatially structured differentiation. We also predicted some reduction in genetic diversity in the peninsular Wyoming portion of the geographic range, relative to its Great Basin core. We used 14 microsatellite loci to compare genetic attributes between geographically distinct pygmy rabbit populations, and a subset of these microsatellite loci to compare with those of 2 sympatric cottontails (Sylvilagus spp.), both presumptive habitat generalists. Pygmy rabbits displayed moderate genetic diversity that was lower than that reported from locations near the core of the geographic range (Idaho and Montana). We observed only low levels of genetic differentiation in pygmy rabbits among sampling sites within Wyoming. Similarly, we observed low levels of differentiation in one species of cottontail sympatric with pygmy rabbits; however, the other species of sympatric cottontail displayed levels of differentiation congruent with those of populations at panmixia. Isolation-by-distance was the dominant genetic pattern observed, although examination of our data suggested that a 4-lane highway (Interstate 80) might affect gene flow measurably. In the recent evolutionary past, habitat connectivity and dispersal capacity for pygmy rabbits have been high enough to maintain gene flow among sites across southern Wyoming. Conservation of the species should focus on maintaining the connectivity among preferred habitats: old stands of big sagebrush.