Earticle

Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.

As an emerging technology for on-chip interconnect scaling in vertical direction in semiconductor industry, through-silicon-via (TSV) demonstrates its advantages and has been adopted for 3D SoC implementation. Optimal test architecture and test scheduling are significant for stacked 3D SoC design. However existing design methods cannot achieve both optimal test time and individual rationality. In this paper, game theory based 3D SoC test architecture optimization and test scheduling method is proposed under constraints of the available number of TSVs for test time minimization and rational test band width allocation. VCG algorithm is brought to 3D SoC design. Three kinds of stacked SoCs are built using ITC’02 SoC test benchmarks, and experimental results on them show the advantages of the proposed method over prior work.

Combinatorial testing has been proved to be an efficient strategy in software testing. The research on automatic test case generation for system level based on components with constraints is a challenging but significant problem by using combinatorial testing. This paper focuses on the test case generation for system level based on components with sequential constraints. There are three main contributions: 1) the new test case generation strategy for system level is proposed based on IPOG (In-Parameter-Order-General) algorithm; 2) a filling strategy for don’t care positions is given to enhance the higher strength coverage for system level, which can improve the quality of the generated test suite; 3) a randomized post-optimization algorithm is applied to reduce the size of the test suite for system level. Experimental results show that the proposed filling strategy can improve the quality of the covering array, the post-optimization algorithm has a good optimization effect on reducing the size of the array, and trades off better between the size of the covering array and computational time than simulated annealing (SA).

Regression testing is a critical activity which occurs during the maintenance stage of the software lifecycle. However, it requires large amounts of test cases to assure the attainment of a certain degree of quality. As a result, test suite sizes may grow significantly. To address this issue, Test Suite Reduction techniques have been proposed. However, suite size reduction may lead to significant loss of fault detection efficacy. To deal with this problem, a greedy algorithm is presented in this paper. This algorithm attempts to select a test case which satisfies the maximum number of testing requirements while having minimum overlap in requirements coverage with other test cases. In order to evaluate the proposed algorithm, experiments have been conducted on the Siemens suite and the Space program. The results demonstrate the effectiveness of the proposed algorithm by retaining the fault detection capability of the suites while achieving significant suite size reduction

The process of verifying the modified software in the maintenance phase is called Regression Testing. The size of the regression test suite and its selection process is a complex task for regression testers because of time and budget constraints. In this research paper, the Bee Colony Optimization (BCO) algorithm for the fault coverage regression test suite prioritization has been presented. In the natural bee colony, there are of two types of worker bees; Scout bees and forager bee, who are responsible for the development and maintenance of the colony. The BCO algorithm developed for the fault coverage regression test suite is based on the behavior of these two bees. The BCO algorithm has been formulated for fault coverage to attain maximum fault coverage in minimal units of execution time of each test case, using two examples whose results are comparable to optimal solution. Average Percentage of Fault Detection (APFD) metrics and charts has been used to show the effectiveness of proposed algorithm.

Test functions play an important role in validating and comparing the performance of optimization algorithms. The test functions should have some diverse properties, which can be useful in testing of any new algorithm. The efficiency, reliability and validation of optimization algorithms can be done by using a set of standard benchmarks or test functions. For any new optimization, it is necessary to validate its performance and compare it with other existing algorithms using a good set of test functions. Optimization problems are widely used in various fields of science and technology. Sometimes such problems can be very complex. Particle Swarm Optimization is a stochastic algorithm used for solving such optimization problems. This paper transplants some of the test functions which can be used to test the performance of Particle Swarm Optimization (PSO) algorithm, in order to improve its performance and have better results. Different test functions can be used for different types of problems. These test functions have a specific range and values, which can be applied in different situations. These functions, when applied to the PSO algorithm, can give the better comparison of results. The test functions that have been the most commonly adopted to assess performance of PSO-based algorithms and details of each of them are provided, such as the search range, the position of their known optima, and other relevant properties.

Objectives. Cultural familiarity and safety must be considered when assessing olfactory ability. The YSK olfactory function (YOF) test is a new olfactory function test using culturally familiar odorants to Koreans. Methods. The YOF test comprises three subtests for threshold (T), discrimination (D), and identification (I). The identification test included eight universal and four Korean culture-friendly odorants, which were selected considering eight major functional groups. Data were obtained from 1,127 subjects over 19 years old. Subjects were classified as having normosmia (n=542), hyposmia (n=472), and anosmia (n=113) by self-reported olfactory function. The YOF test and the Korean version of the Sniffin’ stick test (KVSS-II) were performed on the same day in random order. Diagnostic cutoffs for anosmia and hyposmia were calculated using the Youden index (J). Results. The mean values for each T/D/I subtest and the total TDI score were as follows: normosmia (T, 4.6±2.3; D, 8.6±2.1; I, 11.1±1.7; TDI score, 24.2±4.5); hyposmia (T, 3.3±2.2; D, 7.1±2.5; I, 9.2±3.1; TDI score, 19.5±6.4); and anosmia (T, 1.7±1.2; D, 5.1±2.5; I, 5.0±3.2; TDI score, 11.8±5.6). The correlation coefficients between the YOF test and KVSS-II were 0.57, 0.65, 0.80, and 0.86 for T, D, I, and the TDI score, respectively (P<0.001). The diagnostic cutoffs were a TDI score ≤14.5 (J=0.67) for anosmia and 14.5<TDI score ≤21.0 (J=0.38) for hyposmia. The diagnostic efficacy of the YOF test (area under the curve [AUC], 0.88) was equivalent to that of the KVSS-II (AUC, 0.88; P=0.843; DeLong method). Conclusion. The YOF test is a new olfactory test using safe and Korean culture-friendly odorants. It showed equivalent validity with the conventional olfactory function test. Furthermore, the YOF test provides information on the major functional groups of odorants, potentially enabling a more comprehensive interpretation for patients with olfactory disorders.

In this paper, a procedure is developed for identifying a number of representative solutions manageable for decision-making in a multiobjective optimization problem concerning the test intervals of the components of a safety system of a nuclear power plant. Pareto Front solutions are identified by a genetic algorithm and then clustered by subtractive clustering into "families". On the basis of the decision maker's preferences, each family is then synthetically represented by a "head of the family" solution. This is done by introducing a scoring system that ranks the solutions with respect to the different objectives: a fuzzy preference assignment is employed to this purpose. Level Diagrams are then used to represent, analyze and interpret the Pareto Fronts reduced to the head-of-the-family solutions.

In this study, we have tested the feasibility of the convex non-linear objective model and the line search optimization method for the fluence map optimization (FMO). We've created the convex nonlinear objective function with simple bound constraints and attained the optimal solution using well-known gradient algorithms with an Armijo line search that requires sufficient objective function decrease. The algorithms were applied to 10 head-and-neck cases. The numbers of beamlets were between 900 and 2,100 with a 3 mm isotropic dose grid. Nonlinear optimization methods could efficiently solve the IMRT FMO problem in well under a minute with high quality for clinical cases.

Background: A pooling test is a useful tool for mass screening of coronavirus disease 2019 (COVID-19) in the pandemic era. We aimed to optimize a simple two-step pooling test by estimating the optimal pool size using experimental and mathematical validation. Materials and Methods: Experimental pools were created by mixing one positive respiratory sample with various numbers of negative samples. We selected positive samples with cycle threshold (Ct) values greater than 32 to validate the efficiency of the pooling test assuming a high likelihood of false-negative results due to low viral loads. The positivities of the experimental pools were investigated with a single reverse-transcription polymerase chain reaction (RT-PCR) using the U-TOP™ COVID-19 Detection Kit Plus (Seasun Biomaterials, Daejeon, Korea). We used the Dorfman equation to calculate the optimal size of a pooling test mathematically. Results: Viral RNA could be detected in a pool with a size up to 11, even if the Ct value of a positive sample was about 35. The Dorfman equation showed that the optimal number of samples in a pool was 11 when the prevalence was assumed to be 0.66% based on the test positivity in Daejeon, Korea from April 1, 2020 to November 10, 2020. The efficiency of the pooling test was 6.2, which can save 83.9 of 100 individual tests. Conclusion: Eleven samples in a pool were validated optimal experimentally assuming a prevalence of 0.66%. The pool size needs modification as the pandemic progresses; thus, the prevalence should be carefully estimated before pooling tests are conducted.

In this paper, we propose a novel ant colony optimization (ACO)-based test scheduling method for testing network-on-chip (NoC)-based systems-on-chip (SoCs), on the assumption that the test platform, including specific methods and configurations such as test packet routing, generation, and absorption, is installed. The ACO metaheuristic model, inspired by the ant's foraging behavior, can autonomously find better results by exploring more solution space. The proposed method efficiently combines the rectangle packing method with ACO and improves the scheduling results by dynamically choosing the test-access-mechanism widths for cores and changing the testing orders. The power dissipation and variable test clock mode are also considered. Experimental results using ITC'02 benchmark circuits show that the proposed algorithm can efficiently reduce overall test time. Moreover, the computation time of the algorithm is less than a few seconds in most cases.

Endotoxin has been detected by the Limulus amoebocyte lysate (LAL) test. However, aluminum hydroxide used as an adjuvant and adsorbent for the recombinant protein antigen is known to increase efficacy of lipopolysaccharide vaccine in vivo thus interfering endotoxin test. The aim of this study is to determine effect of aluminum hydroxide on the LAL test using the hepatitis B vaccine as a model and to optimize the LAL test condition not to be interfered by aluminum gydroxide. (omitted)

Stainless steel stamping multistage pump has become the mainstream of civil multi-stage pump. Combined with the technological features of stamping and welding pump, the studies of design for hydraulic parts of pump were come out. An $L_{18}$（$3^7$）orthogonal experiment was designed with seven factors and three values including blade inlet angle, impeller outer diameter, guide vane blade number, etc. 18 plans were designed. The two stage of whole flow field on stainless steel stamping multistage pump at design point for design was simulated by CFD. According to the test result and optimization design with experimental research, the trends of main parameters which affect hydraulic performance were got. After being manufactured and tested, the efficiency of the optimal model pump reaches 61.36% and the single head is more than 4.8 m. Compared with the standard efficiency of 53%, the design of the stainless steel stamping pump is successful. The result would be instructive to the design of Stainless steel stamping multistage pump designed by the impeller head maximum approach.

In this study, the laser soldering process of probe-multilayer ceramic (MLC) substrates was optimized using Type 4 (T4) and Type 7 (T7) Sn-3.0Ag-0.5Cu (SAC305), T7 Sn-0.7Cu solders to improve the high-temperature durability of probe solder joints and satisfy the fine pitch requirements of the soldering process. Thermal cycle tests (TCTs) were performed to compare the heat resistance characteristics of the probe solder joint. The results showed that the bonding strength degradation rates of the SAC305 and Sn-0.7Cu solders after the TCT were within 40% compared to that of the as-soldered state. Because the probe surface and MLC were plated with Ni/Au, various intermetallic compounds (IMCs) were observed at the solder joint. The total IMC thickness of the T7 solder joint was thinner than that of the T4 solder because of the difference in redox reactions according to the particle size of the solder paste. The fracture surface of the probe-MLC solder joint after the shear strength test exhibited a mixed ductile and brittle fracture, and that of the Sn-0.7Cu solder joint exhibited a ductile fracture with numerous dimples.

This study intended to propose a guideline designed to secure safety by developing a functional color design for the color of the ordinary working clothes worn in the actual industrial settings of the machine industry in national industrial complexes in Korea. For this, a total of 6 sets of actual working clothes were produced for test, using 2-color arrangements with blue, of varying brightness and chroma for top and bottom, in relation to the visibility proven in preceding studies and evaluated in the machine industry. Blue was suggested the best proper color for machine industry by previous studies. For the material of working clothes, a total of 111 swatches were collected from the Dongdaemoon Fabric Market, and they were analyzed for color values. A total of 6 materials were used to produce working clothes for testing, which represented high brightness, medium brightness, low brightness, high chroma, medium chroma, and low chroma. Clothes were tried at the industrial settings for machine industry in a national industrial complex located in Gyeongsangnam-do and the expert satisfaction evaluation was performed based on items related with safety. As a result, higher satisfaction was shown when the brightness difference of top and bottom clothes was greater, and for chroma, relatively higher satisfaction appeared when the chroma of both top and bottom clothes was high. To secure satisfaction for both brightness and chroma, it is possible to deduce that the 2-color arrangement using the strong tone with high brightness and high chroma and the dark tone with somewhat low brightness and high chroma would be effective. Top and bottom clothes in the same color with high chroma had high visibility but had somewhat low evaluation for harmonious arrangements. This indicated that the arrangement of vivid colors for top-bottom clothes is inappropriate.

최근 정보 보호가 이슈화됨에 따라 지문인식센서의 활용이 점차 증가하고 있으며, 센서 인식률 오차를 최소화 할 수 있는 품질평가를 요구한다. 지문인식센서 전극과 검사부 프로브 팁이 접촉 시 발생하는 저항 값의 변화에 의해 센서의 품질이 평가되며, 품질평가의 재현성을 확보하기 위해서는 센서 전극의 변형 유발을 최소화할 수 있는 프로브 소재의 적합성과 구조 최적화 연구가 필요하다. 프로브 팁의 적합성 평가를 위한 소재로 니켈(Ni), 스틸(SK4), 베릴륨동(Beryllium copper), 인청동(Phosphor bronze)을 비교하였으며, 프로브 팁 접촉 후 전극의 압흔 크기와 접촉저항을 고려할 때 베릴륨동이 프로브 소재로 적합하다. 검사부 프로브는 지문인식센서 전극의 물리적 손상 방지와 다수의 지문인식센서 동시 검사가 가능한 구조를 위해 일체형 프로브 방식으로 제작하였다. 검사부의 재현성은 특정 전류 값을 인가하여 지문인식센서의 전압 변화로 판단하였으며, 베릴륨동 프로브 소재와 일체형 구조를 통해 센서 전극에 프로브가 300회 접촉하는 동안 센서의 전압 변화는 ${\pm}0.003V$ 이내의 우수한 재현성을 확인하였다.

Recently, fingerprint sensors have widely used for personal information security, and require quality evaluation to reduce an error of their recognition rate. Quality of fingerprint sensors is evaluated by variation of their electrical resistance introducing by contacts between a probe tip and a sensor electrode, Investigation on the materials compatability and structure optimization of probe is required to reduce deformation of sensor electrode for repeatability of quality testing. Nickel, steel(SK4), beryllium copper, and phosphor bronze were considered as probe materials, and beryllium copper was the most appropriate for materials of probe tips, considering indentation and contact resistance while being contacted probe tips on electrodes. Probes of an inspection part were manufactured with the single-unit structure for physical damage prevention and parallel processing capability. Inspection repeatability was evaluated by voltage variation of fingerprint sensors when the specific current was applied. A single-unit inspection part with beryllium copper probe tips showed excellent repeatability within ${\pm}0.003V$ of its voltage variation.

테트로도톡신(tetrodotoxin, TTX)은 강력한 해양생물 유래 신경독소로, 수산물 내 TTX를 검출하기 위해 기존에 주로 사용되는 mouse bioassay (MBA)와 LC-MS/MS 기법은 낮은 검출한계와 동물 윤리 문제 등의 한계가 있어 이를 대체할 새로운 시험법 개발이 필요합니다. Neuro-2a assay는 대표적인 세포기반 대체 시험법으로, 이 방법은 마우스 신경모세포인 Neuro-2a 세포주에 ouabain (O)과 veratridine (V)을 처리하여 과도한 Na+ 유입으로 인한 세포 사멸을 유도한 후, Na+ 채널 억제제인 TTX가 Na+ 유입을 차단해 세포를 보호하는 원리를 이용해 TTX를 정량합니다. 본 연구에서는 Neuro-2a assay를 국내 실험실 환경에 적용하기 위해 TTX 처리 조건과 O/V 농도 등의 매개변수를 최적화하였습니다. 그 결과, 최적 O/V 농도로 600/60 µM를 설정하였으며, S자형 용량-반응 곡선이 도출되는 8가지 농도(50-0.195 ng/mL)를 확인하였습니다. 또한, 24번의 반복 실험을 통해 데이터의 신뢰도를 평가할 수 있는 6가지 data criteria를 확립하였으며, 이 중 EC50 값은 약 3.824-1.268 ng/mL로 나타났습니다. 실험실 간 변동성 비교 결과, COV+와 Bottom OD값을 제외한 모든 품질 관리 기준(quality control criteria)과 데이터 기준(data criteria)의 변동계수(CVs)는 1.31-14.92%로 도출되어, 실험의 적정성과 재현성이 확인되었습니다. 본 연구는 국내에서 활용 가능한 TTX 검출용 Neuro-2a assay의 최적 조건과 신뢰성을 평가할 수 있는 quality control criteria와 data criteria를 제시하였습니다. 아울러, TTX뿐만 아니라 유사체인 4,9-anhydroTTX에 대한 TEF 값을 0.2098로 산출하여, TTX뿐 아니라 다양한 유사체의 검출이 가능함을 확인하였습니다. 향후, 본 시험법은 국내 수산물 내 TTX 검출을 위한 MBA 대체법으로 활용될 것으로 기대됩니다.

Tetrodotoxin (TTX) is a potent marine-derived neurotoxin. Existing detection methods for TTX, such as mouse bioassay (MBA) and LC-MS/MS, are limited by ethical concerns, and low detection thresholds, particularly in the absence of reference standards. Alternative testing methods are thus critically needed. The Neuro-2a assay is a well-established cell-based assay that uses mouse-derived Neuro-2a cells treated with ouabain (O) and veratridine (V), to induce cell death via excessive Na+ influx. This assay quantitates TTX based on its ability to inhibit Na+ influx, thereby allowing the cells to survive. In this study, we optimized parameters including TTX treatment conditions and O/V concentrations, to adapt the Neuro-2a assay for domestic laboratory conditions. The optimal O/V concentrations were determined to be 600/60 µM. We also identified eight concentration points (50-0.195 ng/mL) that generated a sigmoidal dose-response curve. By conducting 24 replicate experiments, we established six key data criteria to ensure reliability, with EC50 values ranging from 3.824 to 1.268 ng/mL. A comparison of inter-laboratory variability revealed that all quality control and data criteria values, except for COV+ and Bottom OD, showed coefficients of variation (CVs) ranging from 1.31 to 14.92%, confirming the assay's accuracy and reproducibility. In this study, we also elucidate optimal assay conditions, validated quality control and data criteria for TTX detection using the Neuro-2a assay in local laboratories. Additionally, we conducted an assay with 4,9-anhydroTTX, a TTX analog, and determined a TEF value of 0.2098, demonstrating the applicability of this method for detecting TTX and its analogs. This optimized Neuro-2a assay is expected to serve as an effective alternative to MBA for detecting TTX in domestic seafood products.