Lock Operations Research Articles

Machine Learning Model-Based Ice Cover Forecasting for a Vital Waterway in Large Lakes

The St. Marys River is a key waterway that supports the navigation activities in the Laurentian Great Lakes. However, high year-to-year fluctuations in ice conditions pose a challenge to decision making with respect to safe and effective navigation, lock operations, and ice breaking operations. The capability to forecast the ice conditions for the river system can greatly aid such decision making. Small-scale features and complex physics in the river system are difficult to capture by process-based numerical models that are often used for lake-wide applications. In this study, two supervised machine learning methods, the Long Short-Term Memory (LSTM) model and the Extreme Gradient Boost (XGBoost) algorithm are applied to predict the ice coverage on the St. Marys River for short-term (7-day) and sub-seasonal (30-day) time scales. Both models are trained using 25 years of meteorological data and select climate indices. Both models outperform the baseline forecast in the short-term applications, but the models underperform the baseline forecast in the sub-seasonal applications. The model accuracies are high in the stable season, while they are lower in the freezing and melting periods when ice conditions can change rapidly. The errors of the predicted ice-on/ice-off date lie within 2–5 days.

A two-layer control architecture for operational management and hydroelectricity production maximization in inland waterways using model predictive control

This work presents the design of a combined control and state estimation approach to simultaneously maintain optimal water levels and maximize hydroelectricity generation in inland waterways using gates and ON/OFF pumps. The latter objective can be achieved by installing turbines within canal locks, which harness the energy generated during lock filling and draining operations. Hence, the two objectives are antagonistic in nature, as energy generation maximization results from optimizing the number of lock operations, which in turn causes unbalanced upstream and downstream water levels. To overcome this problem, a two-layer control architecture is proposed. The upper layer receives external information regarding the current tidal period, and determines control actions that maintain optimal navigation conditions and maximize energy production using model predictive control (MPC) and moving horizon estimation (MHE). This information is provided to the lower layer, in which a scheduling problem is solved to determine the activation instants of the pumps that minimize the error with respect to the optimal pumping references. The strategy is applied to a realistic case study, using a section of the inland waterways in northern France, which allows to showcase its efficacy.

Effect of ship-lock-induced surges on navigation safety in a branched lower approach channel system

Abstract Ships docking and traveling in a branched lower approach channel system are at risk from surges caused by multi-lane locks during emptying operations. For this reason, water-level variations in the lower approach channel in response to discharge, interval running time, and outlet location of lock operations were studied using a 2-D hydrodynamic model validated by physical model tests, and the impact of water level variation on navigation safety under extreme operation scenarios of a quadruple-lane lock group was identified. Results indicated that discharge and interval running time of lock emptying had the greatest impact on the water level variation at the lock head. Water level variation at the lower lock head of the ship lift exhibited a trend of first decreasing and then increasing with the increment of the discharge from the lock chamber into the outer river. Specifically, the surge height at the lock head of the ship lift reached the minimum when approximately 40% of the discharge generated by dual-lane locks during emptying operations was released into the outer river. Overall, the simultaneous operation of quadruple-lane lock group and unit load rejection should be avoided in engineering applications.

An MHE-based MPC strategy for simultaneous energy generation maximization and water level management in inland waterways

This paper proposes a combined control and state estimation strategy for inland waterways, aiming at simultaneously attaining the optimal water level management and maximizing hydroelectricity generation. The latter can be realized by turbines installed in canal locks that harness the energy generated during lock filling and draining operations. These two objectives are of opposed nature, as maximization of energy generation can be achieved by maximizing the number of lock operations, which in turn leads to unbalanced water levels upstream and downstream of the lock. To address this issue, the multi-objective optimization problem is formulated . Then, model predictive control (MPC) and moving horizon estimation (MHE) are designed to maintain navigation conditions in the canals while maximizing energy production. Finally, the proposed strategy is applied to a realistic case study based on part of the inland waterways in the north of France.

Locking by Untuning: A Lock-Less Approach for Analog and Mixed-Signal IC Security

We propose an antipiracy security approach for programmable analog and mixed-signal (AMS) integrated circuits (ICs). The security approach relies on functionality locking by leveraging the inherent programmability and utilizing the configuration settings as secret keys or, equivalently, the programming bits as key bits. When invalid keys are applied, the circuit is untuned and, as a result, its functionality breaks, i.e., at least one of the performances violates its specification. As long as the calibration algorithm that produces the configuration settings can be kept secret, the proposed approach can serve as a countermeasure against all types of counterfeiting, i.e., cloning, overbuilding, remarking, and recycling. An important advantage of the proposed approach is that it is lock-less. It leaves the design intact, there is no change to the design flow, and there are no performance penalty and no area or power overheads due to the lock operation. We demonstrate it on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Sigma \Delta $ </tex-math></inline-formula> analog-to-digital converter (ADC) with 194-bit programmability and complex calibration algorithm used in the context of highly digitized, multistandard RF receivers.

Monitoring of Elastic Deformations of the Hydraulic Structure Gabcíkovo

The settlement and its calculations and monitoring are among the main factors influencing the structure and operability of hydraulic structures. Our paper focuses on the hydraulic structure Gabcíkovo which consists of the hydropower plant with an installed capacity of 720 MW and two navigation locks to ensure international ship transportation. Conventional geodetic methods of classical or very precise leveling with state-of-the-art measuring instruments are currently used to monitor deformations on navigation locks of hydraulic structure Gabcíkovo. In their subsoil, there are gravelly sediments to a depth of about 400 m. Under the gravel sediments, there are Neogene clays and silts. From the beginning of construction, deformations are measured on all structures using special tachymetric devices to monitor the elastic displacements. The obtained measured values are then processed in time dependences and compared with the limit values. During the current almost 30-year operation of the navigation locks, filling and emptying cycles, loading and unloading of the subsoil can be counted in the tens of thousands. The impact of the long-term operation, but especially the current innovation and modernization of navigation locks, aimed at increasing the safety and intensity of transport brings new knowledge and experiences. During the implementation of required improvement related to this project, the right navigation lock is empty for more than a year. The created technical conditions made it possible to monitor the influence of long-term unloading on the subsoil on the vertical displacements in detail. This unusual load condition is a motivation to present the results of measurements in the presented paper.

Optimizing Lock Operations and Ship Arrivals through Multiple Locks on Inland Waterways

Locks are important components of a waterway system. To improve the efficiency of inland waterway transport, it is important to ensure ships passing locks without having to spend unnecessary waiting times at lock entrances. Meanwhile, with the trends towards digitalized and smart waterways, it is also worth investigating how the information availability could contribute to optimizing lock operations and ship arrivals on inland waterways. Therefore, this paper proposes an optimization method to schedule ships’ arrivals and their placements in locks on inland waterways, based on a mixed-integer programming model, and solves the optimization problem with large neighborhood search based heuristics. The optimization objective is threefold: first, optimizing the arrival sequence of ships at the locks; second, maximize the utilization of each lockage operation; and third, reducing the overall time that each ship spends from entering the waterway area till leaving the last lock on the waterway. Simulations are carried out to evaluate the performance of the proposed method.

Lock operations influence upstream passages of invasive and native fishes at a Mississippi River high-head dam

Asian carps continue to expand their range in North America, necessitating efforts to limit the spread and establishment of reproducing populations. Mississippi River Lock and Dam 19 is a high-head dam that represents a population ‘pinch-point’ as passage through the lock chamber is the only means by which fishes can complete upstream movement. As such, this location could be a pivotal control point for minimizing the spread of invasive fishes in the Upper Mississippi River and a possible candidate site for installation of deterrent measures. Our objectives were (1) to study the timing (i.e., weekly and diel) and behavior of fishes in the downstream lock approach, (2) evaluate the relation of presence in the downstream lock approach with environmental factors and lock operation, and (3) identify any upstream or downstream passage events through the lock chamber and the relation between these events and the operation of the lock. Acoustic transmitters were surgically implanted into 262 Asian carps and 216 native fishes to monitor fish activity on a telemetry receiver array deployed around and within the lock for 622 days during 2017–2018. One hundred eighty-six telemetered fish were detected in the downstream lock approach. We documented 14 upstream Asian carp passages and 10 upstream native fish passages; these passages coincided with a specific sequence of large vessel lockages. The results of this study advance our understanding of fish presence and behavior at a Mississippi River mainstem lock and dam and inform the development and testing of deterrent systems at this location or at similar pinch-point lock and dams.

Subharmonic Injection Locking for Phase and Frequency Control of RTD-Based THz Oscillator

Phase and frequency control of resonant tunneling diode (RTD) based terahertz oscillators are major challenges in realizing coherent signal sources for arrayed applications, such as spatial power combining, beam steering, or multi-in multi-out systems. In this letter, we demonstrate frequency locking and control of an RTD oscillating at f 0 ∼ 550 GHz, via radiative injection of a weak sinusoidal subharmonic signal at f 0/2. Precise frequency control, within the locking range of around 2 GHz, is demonstrated. A peak output power enhancement of 14 dB in the whole locking range, compared to the free running oscillator, is achieved. Furthermore, occurrence of phase locking is identified by the spectral linewidth reduction, quantifiable in the full-width at half-maximum parameter. A signal linewidth of 490 Hz was achieved in locked operation.

A molecular device: A DNA molecular lock driven by the nicking enzymes

As people are placing more and more importance on information security, how to realize the protection of information has become a hotspot of current research. As a security device, DNA molecular locks have great potential to realize information protection at the molecular level. However, building a highly secure molecular lock is still a serious challenge. Therefore, taking advantage of the DNA strand displacement and enzyme control technology, we constructed a molecular lock with a self-destructive mechanism. This molecular lock is mainly composed of logic circuits and takes nicking enzymes as inputs. To build this molecular lock, we first constructed a series of cascade circuits, including a YES–YES cascade circuit and a YES–AND cascade circuit. Then, an Inhibit logic gate was constructed to explore the inhibitory properties between different combinations of two nicking enzymes. Finally, using the characteristics of mutual inhibition between several enzymes, a DNA molecular lock driven by three nicking enzymes was constructed. In this molecular device, only the correct sequence of nicking enzymes can be input to ensure the normal operation of the molecular lock. Once the wrong password is entered, the device will be destroyed and cannot be recovered, which effectively prevents intruders from cracking the lock through exhaustive methods. The molecular lock has the function of simulating an electronic keyboard, which can realize the protection of information at the molecular level, and provides a new implementation method for building more advanced and complex molecular devices.

Bismuth triggered selective colorimetric naked-eye detection for oxalate ions based on bromopyrogallol red that works as a molecular keypad lock

ABSTRACT A novel colorimetric probe based on the bromopyrogallol red (BPR) for the sequential detection of Bi3+ and C2O4 2− was designed. The presence of Bi3+ led to a distinct naked-eye colour change in DMSO/H2O (1:3, v/v) media. The detection limit of BPR for Bi3+ was down to nanomolar concentration (1.17 nmol L−1). Also, the sensing ability of BPR for Bi3+ was successfully carried out in bismuth tablet and urine sample. Moreover, the resulting BPR-Bi3+ complex acted as an efficient colorimetric chemosensor for C2O4 2− via a colour change. Therefore, chemosensor BPR-Bi3+ can illustrate the ability to determine C2O4 2- up to 0.15 µmol L−1, selectively. Notably, the absorbance changes of BPR upon the addition of Bi3+ and C2O4 2− were utilised as AND and NAND logic gates operating at the molecular level with Bi3+and C2O4 2− as chemical inputs and the absorbance signal as the output. The chemical inputs of Bi3+ and C2O4 2- in a sequential system produce an output which mimics the operation of a security keypad lock. This study provides a practical application for the sensing of C2O4 2− ions in vegetable and urine samples by the construction of the supramolecular system.

A reversible fluorescence “ON–OFF–ON” sensor for sequential detection of F− and Cu2+ ions and its application as a molecular-scale logic device and security keypad lock

A new azoimine receptor, R1, was synthesized by Schiff base condensation of 4-(4-butylphenyl) azophenol and 2,6-diaminopyridine and acts as a colorimetric and fluorometric chemosensor for F− and also toward Cu2+ ions in aqueous environment. UV–Vis absorption and fluorescent emission spectra were employed to study the sensing process. Emission study was performed to examine the dual sensing ability of the obtained probe with sequential addition of F− followed by Cu2+ and vice versa. The receptor is an efficient “ON–OFF” fluorescent probe for the fluoride ion. Also, R1 + F− operated as an “OFF–ON” fluorescent sensor for Cu2+ ions. Considering emission intensity and absorption wavelength for F− and Cu2+ ions, a molecular system was developed with the ability to mimic the functions of XNOR logic gating on the molecular level. In addition, R1 behaved as a molecular security keypad lock with F− and Cu2+ inputs. The keypad lock operation is particularly important, as the output of the system depends not only on the proper combination but also on the order of input signals, creating the correct password that can be used to “open” this molecular keypad lock through strong fluorescence emission at 460 nm.

Expert control system of shipping operation on the Gabcikovo project

Task of shipping operations control of the Gabcikovo Project is to synchronize several requirements. These come from versatility of GAP and must meet with the following goals. The operation of GAP must be effective (maximization of the ship locks capacity, maximization of income from electricity production in hydropower plant); reliability of operation of the ship locks must not be limited or endangered by defects on technology parts of the ship locks caused by illegal parameters of water flow in the filling and emptying system; and shipping safety must not be endangered or limited by unsuitable parameters of river way (navigable depth below minimal shipping depths in ford sections caused by flow changes on Gabcikovo Project and ships crushing into riverbed of the Danube river). By taking these goals into account, it is possible, in general, to define operation of Gabcikovo Project as complex multi-criteria optimization task with many technological, water management, energetic and environmental constrains...

Faulty Lock Detection and Separation System

All product manufacturing units need to have a faulty product detection and separation system in order to maintain product quality and maintain a good reputation. So here we demonstrate such a system using a mini conveyer belt system. We propose to design and fabricate a faulty product detection and separation mechanism. Each product is different and thus has different mechanisms to detect faulty products. Here we detect fault in lock based on its size and operations. We use a sensor to detect each lock size and operations as products move over a conveyer belt. The conveyer is design so that it can hold the lock so that it does not fall or leave the conveyer belt. A defected product with size lower than minimum limit will be automatically detected as it moves on a conveyer belt and separated by a conveyer arm. If the product passes the size test the next sensor perform it task to operate the lock so that it can open the locking mechanism and check if it opens or not. If the product passes the test it is send for packaging and if not the product is separated and sent to production line for correct the fault. Here we use rollers and rubber belt to develop a mini conveyer belt mechanism. This mechanism is operated by a motor. This system uses servo motor arm to separate the faulty product.

Refactoring Java Programs for Customizable Locks Based on Bytecode Transformation

Developers of parallel programming are faced with choices of using various Java locks. Choosing the best lock is a challenging task because a multithreaded application implemented using different locks may end up with uncertain performance. There is a strong need for automated tool support that helps Java programmers choose the best lock for each specific application. This paper presents an automated transformation approach to convert an implementation using a synchronized lock to a ReentrantLock or a ReentrantReadWriteLock at the bytecode level. For the ReentrantLock, our approach runs analysis for global monitors using the visitor pattern in the Joeq compiler. For the ReentrantReadWriteLock, a read or write lock is chosen after a side-effect analysis. Then, the proposed system validates the consistency of the analysis results to ensure a correct sequence of lock usage. Finally, lock operations and related thread communication operations are transformed into a ReentrantLock or a ReentrantReadWriteLock using a bytecode transformation framework Javassist. We validate our approach on several benchmarks including RBTree, PC, SPECjbb2005, and HSQLDB. The experimental results show that the proposed automated transformation approach can transform these benchmarks successfully in a timely fashion.

Investigating the Mixing Efficiencies of Liquid-to-Liquid Chemical Injection Manifolds for Aquatic Invasive Species Management

Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide) into water can block or kill several invasive organisms and could be a viable option at navigational structures such as lock chambers because chemical infusion would not interfere with vessel passage or lock operation. Chemical treatments near lock structures will require large-scale fluid-mechanic systems and significant energy. Mixing must extend to all stagnation regions within a lock structure to prevent the passage of an invasive fish. This work describes the performance of both wall- and floor-based CO2-infused-water to water injection manifolds targeted for lock structures in terms of mixing time, mixing homogeneity, injection efficiency, and operational power requirements. Both systems have strengths and weaknesses so selection recommendations are given for applications such as open systems and closed systems.

A secrecy-preserving language for distributed and object-oriented systems

In modern systems it is often necessary to distinguish between confidential (low-level) and non-confidential (high-level) information. Confidential information should be protected and not communicated or shared with low-level users. The non-interference policy is an information flow policy stipulating that low-level viewers should not be able to observe a difference between any two executions with the same low-level inputs. Only high-level viewers may observe confidential output. This is a non-trivial challenge when considering modern distributed systems involving concurrency and communication.The present paper addresses this challenge, by choosing language mechanisms that are both useful for programming of distributed systems and allow modular system analysis. We consider a general concurrency model for distributed systems, based on concurrent objects communicating by asynchronous methods. This model is suitable for modeling of modern service-oriented systems, and gives rise to efficient interaction avoiding active waiting and low-level synchronization primitives such as explicit signaling and lock operations. This concurrency model has a simple semantics and allows us to focus on information flow at a high level of abstraction, and allows realistic analysis by avoiding unnecessary restrictions on information flow between confidential and non-confidential data.Due to the non-deterministic nature of concurrent and distributed systems, we define a notion of interaction non-interference policy tailored to this setting. We provide two kinds of static analysis: a secrecy-type system and a trace analysis system, to capture inter-object and network level communication, respectively. We prove that interaction non-interference is satisfied by the combination of these analysis techniques. Thus any deviation from the policy caused by implicit information leakage visible through observation of network communication patterns, can be detected. The contribution of the paper lies in the definition of the notion of interaction non-interference, and in the formalization of a secrecy type system and a static trace analysis that together ensure interaction non-interference. We also provide several versions of a main example (a news subscription service) to demonstrate network leakage.

Effect of Density Differences on the Forces Acting on a Moored Vessel While Operating Navigation Locks

AbstractThis paper investigates the effect of density differences on the forces acting on a moored vessel during lock operations, focusing on the effect of the position of the moored vessel in the ...

SOFRITAS

Correctly synchronizing multithreaded programs is challenging and errors can lead to program failures such as atomicity violations. Existing strong memory consistency models rule out some possible failures, but are limited by depending on programmer-defined locking code. We present the new Ordering-Free Region (OFR) serializability consistency model that ensures atomicity for OFRs, which are spans of dynamic instructions between consecutive ordering constructs (e.g., barriers), without breaking atomicity at lock operations. Our platform, Serializable Ordering-Free Regions for Increasing Thread Atomicity Scalably (SOFRITAS), ensures a C/C++ program's execution is equivalent to a serialization of OFRs by default. We build two systems that realize the SOFRITAS idea: a concurrency bug finding tool for testing called SOFRITEST, and a production runtime system called SOPRO. SOFRITEST uses OFRs to find concurrency bugs, including a multi-critical-section atomicity violation in memcached that weaker consistency models will miss. If OFR's are too coarse-grained, SOFRITEST suggests refinement annotations automatically. Our software-only SOPRO implementation has high performance, scales well with increased parallelism, and prevents failures despite bugs in locking code. SOFRITAS has an average overhead of just 1.59x on a single-threaded execution and 1.51x on sixteen threads, despite pthreads' much weaker memory model.

An Open-Data Based Assessment of Expected Changes in Land Use and Water Availability as a Result of the Construction of the West Segment of the Nicaragua Interoceanic Canal

Nicaragua is preparing the construction of an interoceanic canal that will be the longest and largest canal on Earth. An environmental and social impact assessment was published in 2014 supporting a general viability of the canal. Nonetheless, several scientists and societal actors raised serious concerns regarding the social, economic, and ecological sustainability. Despite an open dispute within the Nicaraguan society, no independent, transparent, and scientifically sound assessment has been carried out. This article presents a transparently documented and comprehensible impact assessment of the West Canal Segment of the Nicaragua Canal. Based on publicly available data and scientifically sound and recognized methods, land use, hydrological (water availability), and socio-economic impacts (population, transportation/communication) are described, quantified, and compared with official declarations in the impact assessment. The examination of official declarations discloses significant ambiguities concerning the methodology and data used for the impact assessment. Consequently, the results presented are at least partly doubtful. When compared with official declarations, the main results of this study reveal: (1) significantly more forested areas (+53.7 km2) and areas of extensive agriculture/near nature (14.4 km2), but far less urban and intensively used areas (−39.6 km2) are affected by the canal; (2) A population of nearly 16,500, and several regional or locally unique transportation and communication routes are directly affected by the canal construction; and (3) a slightly lower water availability (−6.6%) and a much higher water demand for lock operations (+31.8%) were estimated. Accordingly, only about 20% of the lock water demand could be met by locally-available discharge.