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1.
Heliyon ; 10(1): e23586, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38173479

ABSTRACT

Energy consumption and emissions of a vehicle are highly influenced by road contexts and driving behavior. Especially, driving on horizontal curves often necessitates a driver to brake and accelerate, which causes additional fuel consumption and emissions. This paper proposes a novel optimal ecological (eco) driving scheme (EDS) using nonlinear model predictive control (MPC) considering various road contexts, i.e., curvatures and surface conditions. Firstly, a nonlinear optimization problem is formulated considering a suitable prediction horizon and an objective function based on factors affecting fuel consumption, emissions, and driving safety. Secondly, the EDS dynamically computes the optimal velocity trajectory for the host vehicle considering its dynamics model, the state of the preceding vehicle, and information of road contexts that reduces fuel consumption and carbon emissions. Finally, we analyze the effect of different penetration rates of the EDS on overall traffic performance. The effectiveness of the proposed scheme is demonstrated using microscopic traffic simulations under dense and mixed traffic environment, and it is found that the proposed EDS substantially reduces the fuel consumption and carbon emissions of the host vehicle compared to the traditional (human-based) driving system (TDS), while ensuring driving safety. The proposed scheme can be employed as an advanced driver assistance system (ADAS) for semi-autonomous vehicles.

2.
Surg Neurol Int ; 13: 415, 2022.
Article in English | MEDLINE | ID: mdl-36324922

ABSTRACT

Background: Spinal cord infarction is a rare but serious complication of neurointervention that has been rarely documented. An association between spinal cord infarction and the placement of large bore catheters in the vertebral artery (VA) has been mentioned, but the precise etiology remains unclear. Case Description: A 72-year-old female presented with the right hemiparesis and left thermal hypoalgesia directly after endovascular coil embolization for an unruptured basilar tip aneurysm. Magnetic resonance imaging demonstrated right-sided upper cervical (C2-3) spinal cord infarction. Conventional bilateral vertebral angiograms revealed no opacification of the anterior spinal arteries. Cone-beam computed tomography showed a watershed area of radiculomedullary arteries that was correlated with the extent of the ischemic lesion. Thus, the spinal cord ischemia may have had multifactorial causes combined with reduced perfusion pressure to the spinal cord, which was caused by the placement of the guiding catheter in the VA and intensive hypotension during general anesthesia. Conclusion: Spinal cord infarction should be recognized as a serious complication of endovascular treatment involving posterior circulation.

3.
Sensors (Basel) ; 21(19)2021 Sep 30.
Article in English | MEDLINE | ID: mdl-34640852

ABSTRACT

Traditional uncoordinated traffic flows in a roundabout can lead to severe traffic congestion, travel delay, and the increased fuel consumption of vehicles. An interesting way to mitigate this would be through cooperative control of connected and automated vehicles (CAVs). In this paper, we propose a novel solution, which is a roundabout control system (RCS), for CAVs to attain smooth and safe traffic flows. The RCS is essentially a bi-level framework, consisting of higher and lower levels of control, where in the higher level, vehicles in the entry lane approaching the roundabout will be made to form clusters based on traffic flow volume, and in the lower level, the vehicles' optimal sequences and roundabout merging times are calculated by solving a combinatorial optimization problem using a receding horizon control (RHC) approach. The proposed RCS aims to minimize the total time taken for all approaching vehicles to enter the roundabout, whilst minimally affecting the movement of circulating vehicles. Our developed strategy ensures fast optimization, and can be implemented in real-time. Using microscopic simulations, we demonstrate the effectiveness of the RCS, and compare it to the current traditional roundabout system (TRS) for various traffic flow scenarios. From the results, we can conclude that the proposed RCS produces significant improvement in traffic flow performance, in particular for the average velocity, average fuel consumption, and average travel time in the roundabout.

4.
Radiol Case Rep ; 16(9): 2783-2786, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34367395

ABSTRACT

Ostial common carotid artery (CCA) stenosis is rare, compared to extracranial internal carotid artery bifurcation lesions. In cases of a tandem lesion, the proximal lesion usually involves the extracranial internal carotid artery, and the ostial CCA is rarely implicated. A 69-year-old woman who underwent 3 months of antiplatelet therapy for asymptomatic, right ostial, severely calcified CCA stenosis presented with sudden onset left hemiparesis. Radiographic examination revealed an ostial CCA-intracranial artery tandem lesion. After intracranial revascularization using a clot retrieval stent, we performed the endovascular treatment with a balloon-mounted stent using an embolic protection device. This procedure may be superior to others because it is possible to achieve early intracranial revascularization and prevent distal embolism during the complete treatment of proximal lesions.

5.
Asian J Neurosurg ; 16(4): 881-885, 2021.
Article in English | MEDLINE | ID: mdl-35071095

ABSTRACT

We report three cases in which endovascular treatment (EVT) was performed for anterior circulation large vessel occlusion (LVO) beyond 24 h from the onset of stroke. Case 1 experienced left hemispatial neglect and gait disorder due to right internal cerebral artery (ICA) occlusion and underlying atherosclerosis. After percutaneous transluminal angioplasty (PTA), revascularization with mild stenosis was achieved. Case 2 complained of reduced activity, motor aphasia, and right-sided hemiparesis due to left middle cerebral artery occlusion. After thrombectomy using a retrieval stent, revascularization with M1 stenosis and distal perfusion delay was observed, which improved after PTA. Case 3 arrived at our hospital 30 h after the onset of dysarthria and gait disturbance due to left ICA occlusion. Since the symptoms were mild, medical treatment was started; however, the patient's symptoms deteriorated 6 h later, and EVT was required. After thrombectomy using a retrieval stent, revascularization was achieved. LVO pathophysiology beyond 24 h of stroke onset varies and may require multimodal treatment. Preserving the pyramidal tract may lead to favorable outcomes, even in cases of anterior circulation LVO. EVT may be effective for anterior circulation LVO because, in some patients, infarct volume continues to increase >24 h after stroke onset.

6.
NMC Case Rep J ; 8(1): 793-798, 2021.
Article in English | MEDLINE | ID: mdl-35079550

ABSTRACT

Soft tissue calcifications are common findings in patients with various diseases, such as malignant tumors, collagen diseases, trauma, and chronic kidney disease. The majority of these lesions are not clinically significant; however, they can cause specific disorders within a limited space, such as the spinal canal. Here, we report the case of a patient undergoing fusion surgery for lumbar canal stenosis due to degenerative spondylolisthesis and multiple intraspinal canal calcifications associated with psoriatic arthritis (PsA). A 55-year-old female patient presented with pain in the left leg and intermittent claudication for 1 month. One year ago, she was diagnosed with PsA and received outpatient treatment, including biological medication, at the Division of Rheumatology, Department of Internal Medicine of our institution. She was referred to our department, and radiological examination revealed lumbar canal stenosis caused by spondylolisthesis and multiple calcifications in the lumbar spinal canal. We performed posterior lumbar interbody fusion (PLIF) with percutaneous pedicle screw fixation concomitant with removal of the calcifications. The postoperative course was uneventful, and her neurological symptoms improved. Although several prior case reports have noted intraspinal canal calcifications due to collagen disease or chronic kidney disease, calcifications associated with PsA are rare. We discuss the diagnosis of PsA and its relationship with intraspinal canal calcifications by reviewing the previous relevant literature.

7.
No Shinkei Geka ; 47(6): 629-636, 2019 Jun.
Article in Japanese | MEDLINE | ID: mdl-31235665

ABSTRACT

BACKGROUND AND PURPOSE: Warfarin-associated intracranial hemorrhage(w-ICH)usually increases and results in unfavorable outcomes. Administration of prothrombin complex concentrate(PCC)can reverse anticoagulation and correct prothrombin time-international normalized ratio(PT-INR)immediately; it is recommended by some guidelines for cases of w-ICH. We assessed the effect of PCC on blood coagulation. METHODS: We administered PCC and vitamin K to 11 patients with w-ICH who were admitted to our hospital between October 2016 and November 2017. We measured the PT-INR at baseline and immediately, 1 hour, 6 hours, and on the day after PCC administration. RESULTS: Patients' mean(range)PT-INR normalized from 1.92(1.64-3.26)to 1.08(1.03-1.29)immediately after receiving PCC. Patients' PT-INR was 1.17(1.08-1.29)1 hour after receiving PCC, 1.22(1.16-1.52)6 hours after receiving PCC, and 1.17(1.05-1.29)on the day after receiving PCC. In all the cases, no side effects emerged. Five patients had a safe operation. All the patients' modified Rankin Scale scores at discharge were stable or within a permissive limit in comparison with the symptoms on admission. CONCLUSION: In our cases, administration of PCC corrected the PT-INR immediately and contributed to a better outcome of w-ICH.


Subject(s)
Anticoagulants , Intracranial Hemorrhages , Warfarin , Anticoagulants/adverse effects , Blood Coagulation Factors/therapeutic use , Humans , Intracranial Hemorrhages/chemically induced , Intracranial Hemorrhages/drug therapy , Retrospective Studies , Warfarin/adverse effects
8.
Sci Rep ; 3: 1610, 2013.
Article in English | MEDLINE | ID: mdl-23558425

ABSTRACT

The chaotic Boltzmann machine proposed in this paper is a chaotic pseudo-billiard system that works as a Boltzmann machine. Chaotic Boltzmann machines are shown numerically to have computing abilities comparable to conventional (stochastic) Boltzmann machines. Since no randomness is required, efficient hardware implementation is expected. Moreover, the ferromagnetic phase transition of the Ising model is shown to be characterised by the largest Lyapunov exponent of the proposed system. In general, a method to relate probabilistic models to nonlinear dynamics by derandomising Gibbs sampling is presented.


Subject(s)
Computing Methodologies , Models, Statistical , Neural Networks, Computer , Nonlinear Dynamics , Computer Simulation , Feedback
9.
Sci Rep ; 3: 1127, 2013.
Article in English | MEDLINE | ID: mdl-23350034

ABSTRACT

The green and red lights of a traffic signal can be viewed as the up and down states of an Ising spin. Moreover, traffic signals in a city interact with each other, if they are controlled in a decentralised way. In this paper, a simple model of such interacting signals on a finite-size two-dimensional lattice is shown to have Ising-like dynamics that undergoes a ferromagnetic phase transition. Probabilistic behaviour of the model is realised by chaotic billiard dynamics that arises from coupled non-chaotic elements. This purely deterministic model is expected to serve as a starting point for considering statistical mechanics of traffic signals.

10.
Philos Trans A Math Phys Eng Sci ; 368(1930): 4977-93, 2010 Nov 13.
Article in English | MEDLINE | ID: mdl-20921007

ABSTRACT

In terms of a piecewise affine system representation, which is a kind of hybrid system model, this article discusses a series of approaches to modelling, analysing and synthesizing a biological network such as a gene-regulatory network. First, the input assignment problem, the controllable state set problem (CSP) and the input trajectory generation problem are emphasized as control problems to be addressed for biological networks. Subsequently, after the modelling issue on biological networks developed in the systems and control community is briefly explained, the CSP is described in detail with reference to control of the quorum-sensing system in the pathogen Pseudomonas aeruginosa. Finally, an optimal control design method to the quorum-sensing system is proposed as a solution to the input trajectory generation problem.


Subject(s)
Gene Expression Regulation , Models, Biological , Nonlinear Dynamics , Signal Transduction , Pseudomonas aeruginosa/growth & development , Quorum Sensing/physiology
11.
Article in English | MEDLINE | ID: mdl-20885776

ABSTRACT

In recent years, Boolean-network-model-based approaches to dynamical analysis of complex biological networks such as gene regulatory networks have been extensively studied. One of the fundamental problems in control theory of such networks is the problem of determining whether a given substance quantity can be arbitrarily controlled by operating the other substance quantities, which we call the controllability problem. This paper proposes a polynomial-time algorithm for solving this problem. Although the algorithm is based on a sufficient condition for controllability, it is easily computable for a wider class of large-scale biological networks compared with the existing approaches. A key to this success in our approach is to give up computing Boolean operations in a rigorous way and to exploit an adjacency matrix of a directed graph induced by a Boolean network. By applying the proposed approach to a neurotransmitter signaling pathway, it is shown that it is effective.

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