Navigation Software Research Articles

Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction for bone sarcomas: long-term outcomes.

Background:Computed tomography (CT) and magnetic resonance imaging (MRI) data can be fused to identify the tumor boundaries. This enables surgeons to set close but tumor-free surgical margins and excise the tumor more precisely. This study aimed to report our experience in performing computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction to treat bone sarcoma in the diaphysis and metaphysis of the femur and tibia.Methods:Between September 2008 and December 2015, 24 patients with bone sarcomas underwent surgical resection and joint-sparing reconstruction under image-guided computer navigation. The cohort comprised 16 males and eight females with a median age of 19.5 years (range: 12–48 years). The tumor location was the femoral diaphysis in three patients, distal femur in 19, and proximal tibia in two. The tumors were osteosarcoma (n = 15), chondrosarcoma (n = 3), Ewing sarcoma (n = 3), and other sarcomas (n = 3). We created a pre-operative plan for each patient using navigation system software and performed navigation-aided resection before reconstructing the defect with a custom-made prosthesis with extracortical plate fixation.Results:Pathological examination verified that all resected specimens had appropriate surgical margins. The median distance from the tumor resection margin to the joint was 30 mm (range: 13–80 mm). The median follow-up duration was 62.5 months (range: 24–134 months). Of the 24 patients, 21 remain disease free, one is alive with disease, and two died of the disease. One patient developed local recurrence. Complications requiring additional surgical procedures occurred in six patients, including one with wound hematoma, one with delayed wound healing, one with superficial infection, one with deep infection, and two with mechanical failure of the prosthesis. The mean Musculoskeletal Tumor Society score at the final follow-up was 91% (range: 80%–100%). The 5- and 10-year implant survival rates were 91.3% and 79.9%, respectively.Conclusions:Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction with extracortical plate fixation is a reliable surgical treatment option for bone sarcoma in the diaphysis and metaphysis of the femur and tibia.

Virtual autopsy and confirmation of normal fetal heart anatomy in the first trimester using three-dimensional (3D) reconstruction of histological sections.

Objective: In this pilot study, we tested the feasibility of cardiac structures reconstruction from histological sections in 12–13 weeks normal fetuses. Conventional autopsy is hampered at this gestational age because of the small size of the heart anatomical structures, while alternative non-invasive methods for pathology examination of the fetus are expensive, rarely available and lack accuracy data regarding the confirmation of first trimester heart defects suspected by early prenatal ultrasound (US) scans. Materials and Methods: Normal hearts from fetuses aged 12–13 gestational weeks (GW) were harvested for histological preparation, virtual reconstruction, and cardiac structures analysis. The normalcy of heart structures was confirmed before pregnancy termination, using a detailed US scan protocol. The fetal heart was routinely processed for formalin fixation and paraffin embedding (FFPE) and 10 μm seriate sections have been cut until finishing the specimen. All sections have been scanned and a three-dimensional (3D) reconstruction of the whole organ has been rendered, based on computer-aided manual tracing. Using the 3D navigation software, the main cardiac structures were searched for a proper and confident visualization. Results: Five cases were investigated. Visualization of the normal heart cavities, including atrioventricular septum was very good in all fetuses. The entire course of right and left ventricle outflow tracts was confidently confirmed, along the branching pattern of aorta and pulmonary artery trunk. Regarding the veno-atrial connections, it was easy to identify the entrance of the inferior and superior caval veins into the right atrium, but a detailed review of the histological sections was necessary for the visualization of the left atrium venous openings. The inherent morphological deformation following heart block sectioning resulted in a lower resolution or quality of the “reconstructed” planes, but these distortions did not represent a significant impediment in any of the cases. The resources involved ordinary histology and information technology (IT) equipment. To further decrease the time involved by the protocol, many steps may be automated: cutting, coloring, and scanning. Conclusions: The results indicate that this method can be implemented to routine clinical practice. The use of 3D reconstruction of fetal heart histological sections in first trimester may serve as an important audit to confirm the normalcy of heart structures. Also, the histological and postprocessed information is retained, and this volume can be stored, reanalyzed, or sent online for a second opinion. The method involves relatively undemanding resources, i.e., hardware, software, competences, and time. The procedure could also benefit from refinements used in other imaging techniques to limit human–computer interactions, such as sections distortion.

Three-dimensional attachment morphometry and volumetric changes of masticatory muscles after free fibular flap reconstruction of the mandibular condyle

This retrospective case-series study aimed to elucidate the three-dimensional attachment morphometric features and to quantify the volumetric changes of the masticatory muscles following free fibular flap reconstruction of the mandibular condyle. Navigation software (iPlan, version 3.0; Brainlab) was used to perform delineation and volumetric measurement of the masticatory muscles using DICOM data.In total, 30 patients were included in this retrospective case series. In 25 cases (83.33%), the lateral pterygoid muscle achieved reattachment within 6 months postoperatively. The medial pterygoid muscles on the affected side achieved ectopic attachment in all cases. However, masseter reattachment on the affected side was achieved in only three cases. On the normal side, the volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter had recovered to almost preoperative levels at 1 year postoperatively. On the affected side, the volume of medial pterygoid muscle had decreased significantly (p = 2.4e-04) at 3 months postoperatively. The volumes of lateral pterygoid muscle and masseter showed mild decreases at 3 months postoperatively, but these were not significant (p = 0.52 and p = 0.05 for the pterygoid muscle and masseter, respectively). At 6 months after surgery, with the exception of the volume of the lateral pterygoid muscle (p = 0.06), the total volume of the masticatory muscles decreased significantly on the affected side. The volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter showed significant decreases at 1 year postoperatively (p = 0.03, p = 4.7e-08, and p = 1.1e-05, respectively) on the affected side. The postoperative volumes of the masseter, medial pterygoid, and lateral pterygoid muscles showed significant decreases due to the loss of reattachment.The results of this study may not help to ascertain whether reattachment of masticatory muscles will lead to better function. As a consequence, clinical trials of higher quality are needed.

Evaluation of Cultural Intelligence in Sports Management through Country Navigator Software

Evaluation of Cultural Intelligence in Sports Management through Country Navigator Software

Comparative Study of Supervised Machine Learning Algorithms for Predicting the Compressive Strength of Concrete at High Temperature.

High temperature severely affects the nature of the ingredients used to produce concrete, which in turn reduces the strength properties of the concrete. It is a difficult and time-consuming task to achieve the desired compressive strength of concrete. However, the application of supervised machine learning (ML) approaches makes it possible to initially predict the targeted result with high accuracy. This study presents the use of a decision tree (DT), an artificial neural network (ANN), bagging, and gradient boosting (GB) to forecast the compressive strength of concrete at high temperatures on the basis of 207 data points. Python coding in Anaconda navigator software was used to run the selected models. The software requires information regarding both the input variables and the output parameter. A total of nine input parameters (water, cement, coarse aggregate, fine aggregate, fly ash, superplasticizers, silica fume, nano silica, and temperature) were incorporated as the input, while one variable (compressive strength) was selected as the output. The performance of the employed ML algorithms was evaluated with regards to statistical indicators, including the coefficient correlation (R2), mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE). Individual models using DT and ANN gave R2 equal to 0.83 and 0.82, respectively, while the use of the ensemble algorithm and gradient boosting gave R2 of 0.90 and 0.88, respectively. This indicates a strong correlation between the actual and predicted outcomes. The k-fold cross-validation, coefficient correlation (R2), and lesser errors (MAE, MSE, and RMSE) showed better performance than the ensemble algorithms. Sensitivity analyses were also conducted in order to check the contribution of each input variable. It has been shown that the use of the ensemble machine learning algorithm would enhance the performance level of the model.

Ontology-based approach to data exchanges for robot navigation on construction sites

As the use of autonomous Unmanned Ground Vehicles (UGV) for automated data collection from construction projects increases, construction stakeholders have become aware of a problem with inter-disciplinary semantic data sharing and exchanges between construction and robotic. Cross-domain data translation requires detailed specifications especially when it comes to semantic data translation. Building Information Modeling (BIM) and Geographic Information System (GIS) are the two digital building technologies used to capture and store semantic information for indoor structures and outdoor environments respectively. In the absence of a standard format for data exchanges between the construction and robotic domains, the tools of both industries have yet to be integrated into a coherent deployment infrastructure. In other words, the semantics of BIM-GIS cannot be automatically integrated by the robotic platforms currently being used. To enable semantic data transfer across domains, semantic web technology has been widely used in multi-disciplinary areas for interoperability. This paves the way to smarter, quicker and more precise robot navigation on construction sites. This paper develops a semantic web ontology integrating robot navigation and data collection to convey the meanings from BIM-GIS to the robot. The proposed Building Information Robotic System (BIRS) provides construction data that are semantically transferred to the robotic platform and can be used by the robot navigation software stack on construction sites. To meet this objective, first, knowledge representation between construction and robotic domains is bridged. Then, a semantic database integrated with the Robot Operating System (ROS) is developed, which can communicate with the robot and the navigation system to provide the robot with semantic building data at each step of data collection. Finally, the BIRS proposed system is validated through four case studies.

Natural language understanding of map navigation queries in Roman Urdu by joint entity and intent determination.

Navigation based task-oriented dialogue systems provide users with a natural way of communicating with maps and navigation software. Natural language understanding (NLU) is the first step for a task-oriented dialogue system. It extracts the important entities (slot tagging) from the user’s utterance and determines the user’s objective (intent determination). Word embeddings are the distributed representations of the input sentence, and encompass the sentence’s semantic and syntactic representations. We created the word embeddings using different methods like FastText, ELMO, BERT and XLNET; and studied their effect on the natural language understanding output. Experiments are performed on the Roman Urdu navigation utterances dataset. The results show that for the intent determination task XLNET based word embeddings outperform other methods; while for the task of slot tagging FastText and XLNET based word embeddings have much better accuracy in comparison to other approaches.

Time-saving effects using helicopter transportation: comparison to a ground transportation time predicted using a social navigation software.

Previous comparison studies regarding 2 types of transportation, helicopter (HEMS) versus ground emergency medical services (GEMS), have shown underlying heterogeneity as these options have completely different routes and consequent times with reference to one patient. To compare the 2 types of transportation on a case-by-case basis, we analyzed the retrospectively reviewed HEMS and predicted GEMS data using an open-source navigation software.Patients transferred by military HEMS from 2016 to 2019 were retrospectively enrolled. The HEMS records on the time of notification, injury point and destination address, and time required were reviewed. The GEMS data on distance and the predicted time required were acquired using open-source social navigation systems. Comparison analyses between the two types of transportation were conducted. Furthermore, linear logistic regression analyses were performed on the distance and time of the two options.A total of 183 patients were enrolled. There was no statistical difference (P = .3021) in the distance between the 2 types of transportation, and the HEMS time was significantly shorter than that of GEMS (61.31 vs 116.92 minutes, P < .001). The simple linear curves for HEMS and GEMS were separately secured, and two graphs presented the statistical significance (P) as well as reasonable goodness-of-fit (R2). In general, the HEMS graph demonstrates a more gradual slope and narrow distribution compared to that of GEMS.Ideally, HEMS is identified as a better transportation modality because it has a shorter transportation time (56 minutes saved) and a low possibility of potential time delays (larger R2). With a strict patient selection, HEMS can rescue injured or emergent patients who are “out of the golden hour.”

Is the Greater Trochanter the Ideal Freehand Landmark for the S2AI Screw Angle in the Caudal Direction? Commentary on “Extra-articular Portion of the Sacroiliac Joint—Between the Sacral and Pelvic Tuberosities: An Anatomical Guide for the S2-Alar-Iliac Screw Trajectory” by Tatara et al

The author introduced a novel freehand technique for S2-Alar-Iliac screw placement Which demonstrated good clinical safety. However the optimal anatomical landmarks of the screw angle in the caudal direction have not been unified. The tip of the greater trochanter(TGT) was one of the most frequently chosen landmark in fluoroscopic or navigation guidance technique. Additional adjustments are always needed according to these studies. The freehand technique of the present study also choose the TGT as the as the landmark of the S2AI screw angle in the caudal direction, whether it also need any adjustment? We hope the author could explain more about this issue. Besides, the relationship between TGT and the sacral iliac bone is not static, which will make the reliability of the pre-surgery navigation software simulation doubtful.

Model-Based Slippage Estimation to Enhance Planetary Rover Localization with Wheel Odometry

The exploration of planetary surfaces with unmanned wheeled vehicles will require sophisticated software for guidance, navigation and control. Future missions will be designed to study harsh environments that are characterized by rough terrains and extreme conditions. An accurate knowledge of the trajectory of planetary rovers is fundamental to accomplish the scientific goals of these missions. This paper presents a method to improve rover localization through the processing of wheel odometry (WO) and inertial measurement unit (IMU) data only. By accurately defining the dynamic model of both a rover’s wheels and the terrain, we provide a model-based estimate of the wheel slippage to correct the WO measurements. Numerical simulations are carried out to better understand the evolution of the rover’s trajectory across different terrain types and to determine the benefits of the proposed WO correction method.

An Axiom of True Courses Calculation in Great Circle Navigation

Based on traditional expressions and spherical trigonometry, at present, great circle navigation is undertaken using various navigational software packages. Recent research has mainly focused on vector algebra. These problems are calculated numerically and are thus suited to computer-aided great circle navigation. However, essential knowledge requires the navigator to be able to calculate navigation parameters without the use of aids. This requirement is met using spherical trigonometry functions and the Napier wheel. In addition, to facilitate calculation, certain axioms have been developed to determine a vessel’s true course. These axioms can lead to misleading results due to the limitations of the trigonometric functions, mathematical errors, and the type of great circle navigation. The aim of this paper is to determine a reliable trigonometric function for calculating a vessel’s course in regular and composite great circle navigation, which can be used with the proposed axioms. This was achieved using analysis of the trigonometric functions, and assessment of their impact on the vessel’s calculated course and established axioms.

Hardware in the Loop Topology for an Omnidirectional Mobile Robot Using Matlab in a Robot Operating System Environment

The symmetry of the omnidirectional robot motion abilities around its central vertical axis is an important advantage regarding its driveability for the flexible interoperation with fixed conveyor systems. The paper illustrates a Hardware in the Loop architectural approach for integrated development of an Ominidirectional Mobile Robot that is designed to serve in a dynamic logistic environment. Such logistic environments require complex algorithms for autonomous navigation between different warehouse locations, that can be efficiently developed using Robot Operating System nodes. Implementing path planning nodes benefits from using Matlab-Simulink, which provides a large selection of algorithms that are easily integrated and customized. The proposed solution is deployed for validation on a NVIDIA Jetson Nano, the embedded computer hosted locally on the robot, that runs the autonomous navigation software. The proposed solution permits the live connection to the omnidirectional prototype platform, allowing to deploy algorithms and acquire data for debugging the location, path planning and the mapping information during real time autonomous navigation experiments, very useful in validating different strategies.

A Novel Tracker-Less, Universal, Image-Based, Computer-Assisted Navigation in Orthopaedic Trauma- A pilot Study.

Computer-assisted navigation system is well-known orthopaedic advancement which allow surgeon to obtain a real-time feedback during surgeries, thus helps to reduce intraoperative errors. Currently used navigation systems are tracker based, invasive and non-universal. Therefore this study was conducted to test novel tracker-less, image-based, non-invasive, universal, real-time navigation system to predict future position of the guide wire, K wire, screws and plates in orthopaedic trauma surgeries. Firstly, the software was tested and validated on bone model. Then utilized for non-randomised comparative study conducted on 81 adult patients with stable intertrochanteric fracture treated by dynamic hip screw and barrel plate fixation. In one group, C-arm was used and in other, software navigation was used in addition to C-arm. Parameters such as time to insertion, number of C-arm shoots and number of attempts for guide wire insertion were documented and compared. Use of the navigation software for guide wire positioning in bone models and in the DHS barrel plate surgery proved to be significantly beneficial as compared to not using navigation. Intraoperative use of this new navigation system eliminates trial and error improving accuracy and reducing the operative time and radiation exposure. Thus this novel trackerless, C-arm image-based navigation system have potential to replace existing tracker-based navigation systems because of its universal nature, noninvasive and more effective properties.

Challenges and Opportunities of Intraoperative 3D Ultrasound With Neuronavigation in Relation to Intraoperative MRI.

IntroductionNeuronavigation greatly improves the surgeons ability to approach, assess and operate on brain tumors, but tends to lose its accuracy as the surgery progresses and substantial brain shift and deformation occurs. Intraoperative MRI (iMRI) can partially address this problem but is resource intensive and workflow disruptive. Intraoperative ultrasound (iUS) provides real-time information that can be used to update neuronavigation and provide real-time information regarding the resection progress. We describe the intraoperative use of 3D iUS in relation to iMRI, and discuss the challenges and opportunities in its use in neurosurgical practice.MethodsWe performed a retrospective evaluation of patients who underwent image-guided brain tumor resection in which both 3D iUS and iMRI were used. The study was conducted between June 2020 and December 2020 when an extension of a commercially available navigation software was introduced in our practice enabling 3D iUS volumes to be reconstructed from tracked 2D iUS images. For each patient, three or more 3D iUS images were acquired during the procedure, and one iMRI was acquired towards the end. The iUS images included an extradural ultrasound sweep acquired before dural incision (iUS-1), a post-dural opening iUS (iUS-2), and a third iUS acquired immediately before the iMRI acquisition (iUS-3). iUS-1 and preoperative MRI were compared to evaluate the ability of iUS to visualize tumor boundaries and critical anatomic landmarks; iUS-3 and iMRI were compared to evaluate the ability of iUS for predicting residual tumor.ResultsTwenty-three patients were included in this study. Fifteen patients had tumors located in eloquent or near eloquent brain regions, the majority of patients had low grade gliomas (11), gross total resection was achieved in 12 patients, postoperative temporary deficits were observed in five patients. In twenty-two iUS was able to define tumor location, tumor margins, and was able to indicate relevant landmarks for orientation and guidance. In sixteen cases, white matter fiber tracts computed from preoperative dMRI were overlaid on the iUS images. In nineteen patients, the EOR (GTR or STR) was predicted by iUS and confirmed by iMRI. The remaining four patients where iUS was not able to evaluate the presence or absence of residual tumor were recurrent cases with a previous surgical cavity that hindered good contact between the US probe and the brainsurface.ConclusionThis recent experience at our institution illustrates the practical benefits, challenges, and opportunities of 3D iUS in relation to iMRI.

Development of a combined navigation and measurement system for manned airborne geophysical measurements

The article is devoted to the idea of combining navigation and measurement software to provide a higher level of efficiency and quality of aerial electromagnetic survey. Complex geophysical measurement systems of “Impulse-Aero” series are overviewed. Current survey technology with the above-mentioned systems includes human-based control of the measurements with a geophysicist on-board. The technology also includes the navigational support by the geophysicist or an additional navigation specialist. The concept of automatic combined complex for navigational and measurement monitoring is proposed in the article. The main goal of the system under analysis is to automatically estimate the quality of received data and to give necessary recommendations on the screen of the navigation unit. As the result of the survey, some tasks during the flight can be solved by pilots without any additional staff. This approach is supposed to increase flight safety, reduce costs and raise the efficiency of the survey in general.

다수 차량 표시 항법시스템 개발

초록 · 키워드 목차 오류제보하기 In this paper, a multi-vehicle display navigation system is developed. The system enables the display of another vehicle’s position together with the vehicle"s own position. The system"s hardware is composed of an android mobile phone, a computer, and Wi-Fi equipment. The software includes multi-vehicle display navigation software, an android app installed on the mobile phone, and a socket program for communication. The navigation software receives the position sent from the other vehicle via the mobile phone and displays that position together with its own position. Visual C++ and Java are used to develop the navigation system software and the android software, respectively. Navigation position data collected through real driving tests are used to validate the developed system. #multi-vehicle display #car navigation #GPS AbstractI. 서론II. 다수 차량 위치 표시 항법시스템 개발III. 실험 결과 및 분석IV. 결론REFERENCES

SPLE 기반 관성항법시스템 소프트웨어 플랫폼 개발을 위한 구조설계

본 논문에서는 유도무기체계와 무인기체계 개발에 공통적으로 활용될 수 있는 관성항법시스템 소프트웨어를 대상으로 SPL(Software Product Line)의 핵심 자산(Core Assets)인 소프트웨어 플랫폼 개발을 위한 구조설계 방법과 아키텍처적 주요 설계 결정사항에 대한 연구결과를 소개한다. 우선 소프트웨어 플랫폼 아키텍처 모델링을 위해 개념 뷰, 실행 뷰, 배포 뷰로 구성된 Three Views 방법을 제안한다. 제안한 방법에 따른 논리 컴포넌트 설계 내용으로 관성항법시스템 소프트웨어의 기능과 가변성을 고려하여 논리 컴포넌트 그룹과 그룹에 포함되는 논리 컴포넌트들로 구성되는 두 단계의 계층구조를 갖는 논리 컴포넌트를 설계한다. 물리 컴포넌트 설계 내용으로 실시간 제어를 위해 연산량이 복잡한 태스크와 주 제어 태스크를 분리하는 설계를 수행한다. 이러한 설계의 기본 원칙이 되는 주요 아키텍처적 설계 결정사항과 각 사항에 대한 결정 이유, 대안 분석 내용을 제시한다.

Calibrating Best Route Based on Battery Percentage and Availability of Charging Station

The electric vehicle market is increasing rapidly. Smart cars and AI integrated cars are under development for automatic driving. Embedded software is necessary for an electric vehicle to function properly. Almost all cars have inbuilt software navigation purposes. The user’s main concern about electric vehicles is the driving range. Electric cars having an inbuilt navigation system that indicates appropriate charging points suitable for the user. The planning route is essential to reach the destination before the battery dies. The software can provide a solution here by analyzing and optimizing the data which is stored in the cloud. Battery swapping can also be done by booking batteries at charge stations before the time of travel. This solution will promote users to drive electric vehicles for even long travels.

Taking a Closer Look at Distance: Does Increasing the Maximal Donor Distance Range Shorten Waitlist Times in Pediatric Heart Transplant Candidates?

<h3>Purpose</h3> Data suggest that pediatric heart transplant (HT) centers can reduce waitlist time by expanding donor catchment vis expanded parameters including the maximal donor weight range. Contrary to donor weight ranges, little is known about the effect of increasing the donor distance (DD) range. We sought to determine whether increasing the DD range can reduce waitlist time and how well actual DD predicts ischemic time (IT). <h3>Methods</h3> All US children <18 years listed for HT at centers with ≥20 HT since 2007 were identified using OPTN data. Center variation in maximal DD range, defined as the median value of a center's maximal DD range, was analyzed and compared to actual DD. Pearson correlation was used to examine the correlation between actual DD and IT. Cox proportional hazards analysis was used to determine whether maximal DD range is associated with waitlist time. <h3>Results</h3> Among 4,240 children who met study criteria, the median age was 2 (IQR 0, 11) years, weight 12 (6, 35) kg, 53% had CHD. Centers varied considerably in their maximal DD range (1000-10,000 miles); median 1500 miles (Figure A). Overall, 86% of donors originated from ≤500 miles; 97% ≤1,000 miles (Figures A & B) with sharp drop-offs at 500 and 1000 miles (Figure B). After adjusting for patient factors, maximal DD range was associated with a shorter waitlist time. The correlation between actual DD and IT is fair (R=0.69) but explains only half (R²=0.49) of the variability in IT. <h3>Conclusion</h3> Pediatric HT centers vary considerably in their maximal donor distance ranges, though most donors still fall within 500-1000 miles of recipients. Increasing the maximal DD range appears is associated with a shorter waitlist time. Actual DD explains only half of the variability in IT. Further research is needed to understand the optimal regional sharing distance for organ allocation and whether contemporary navigational software could better predict IT than the linear distance to the donor hospital.

Simulations suggest that navigation software may not be as efficient as expected for city traffic.

We suggest a theoretical framework to study the dynamics of an open city, with cars entering at a certain rate and leaving as they reach their destinations. In particular, we assess through simulations some unexpected consequences of the massive use of GPS (global positioning system) navigation systems in the overall dynamics. One of our main interest is to identify what type of measurements would be the most relevant for an experimental study of this system, specifically, the ones useful for city traffic administrators. To do so, we solve the microdynamics using a cellular automaton model considering three different navigation strategies based on the minimization of the individual paths (unweighted strategy) or travel times (weighted strategies). Although the system is inherently stochastic, we found in our simulations an equivalent saddle-node bifurcation for all strategies where the input rate acts as a bifurcation parameter. There is also evidence of additional bifurcations for travel time minimization based strategies. Although we found that weighted strategies are more efficient in terms of car motion, there is a destabilization phenomenon that makes, in an unexpected way, a variation of the unweighted strategy more optimal at certain densities from the fuel efficiency of the overall city traffic point of view. These results bring new insight into the intrinsic dynamics of cities and the perturbations that individual traffic routing can produce on the city as a whole.